Still has my no vote.

It's fine by me, I'm pretty sure you had a fair number of suggestions I disagreed with in the past, in the present, and most likely in the future.
The suggestion to get more base slots isn't going to make loyalty boxes or GA useless, because people use GAs for other reasons, namely the autopricer and the extra quests, and the loyalty box is still going to be used, because it's the only way to bypass the hard slot cap.
I really like this idea! Although, perhaps instead of making them free from the get-go, perhaps they could be implemented in any one of a number of ways that contribute to SP sinking to help prevent people from trying to circumvent the rules with mules:
-Achievement based on completing x amount of 'new user' achievements -Outright purchasing the extra pet slots with SP via the MC or something -Granted after x amount of days (probably 30, to match the adoption/abandon time limit)
Per user, that's a potential for $25 from custom overlays, and about $35 a month from auto-training that may not have been spent otherwise. Of course, there's always the potential that people are going to use SP to purchase this CSC, but that's neither here nor there because there will always be people who spend money on the site, and the more valuable CSC is the more likely people are to spend it.
Hey, do you mind if I had your post to the first post, because you have calculations, excellent arguments, and I can live with SP alternatives very well.
Overall, everything in your post is very, very good!
I like the idea of unlocking the extra slots. I would be ok with that. :) That sounds like a good way to get people involved in the site, which is always a big plus.

I agree. Unlocking more than 5 seems better than just being given 5, because it encourages people to stick around longer than just a couple of days to create 10 pets, get bored, and leave. You could add it to the newbie guide with links to different site features, and if you finish xyz tasks, you unlock the extra slots or something.
I am way to lazy to read through all the comments but I do want to contribute to say that I support the increase in whatever way.
I've personally always thought that the base number of pets should go up 1 each year you're on here. And I know what a lot of people will say, you can get an extra pet slot from the loyalty box, but I think it makes more sense to automatically gain a base pet. For example if someone just does not have the money to spend on CSC they can get these extra pet slots AND they don't need to use a GA to fill it.
Just give us the chance for more pet slots, be it free or otherwise, or the ones that require your soul or something.

Problem with sticking them in the newbie guide = what about the older users? Because we don't have access to the newbie guide. Maybe just stick them to achievements related to newbie things and then explain that in the newbie guide?
a.k.a things like:
Just throwing some numbers around.
Basic things that encourage site use for newer users and not just here have 10 slots to start with I remember as a newbie i was thrilled to get new pets because i came from neo where pet art is boring and all art here is way above neo level. So giving 5 slots away with relatively easy achievements might encourage players to stick around for longer than a day and to work towards a goal.
[edit] Next up on the suggestion forums:

Yeah, I didn't mean they had to be done through the newbie guide. But the guide could have the information listed ("If you do xyz listed here you can unlock 5 more pets" complete with links. Older users can find the things themselves/they would probably be linked in the news post announcing this)
But I like your ideas too. Even if they're not retroactive once added, none of those things should be much of a problem to get done
I'm totally okay with unlocking the slots through certain activities but only if everyone has the chance and not just new users. points at newbie guide I'll riot if I miss out on a slot, you know? :P
It might make more sense to have the tasks pet-oriented, so you have to spend time with your current pets to earn more slots. So things like training, feeding, coloring them, getting nominated for the pet spotlight, purchasing TC slots, reading books, etc. Page views (F5 F5 F5) and quests are a little sidetracked, I think.
And I have no problems with the requirements being higher, like training a pet to level 250. It's a good stretch goal for new players, so they're not unlocking the extra slots on day 1.
You could just make these achievements (or use existing achievements, as necessary) and have the reward be a Loyalty Pet Slot Totem. That should be super easy to set up. Just make sure to mention these achievements in the newbie guide so they know what to do.

They can be put in the newbie guide. Staff just have to reset it to give access to the newbie guide to everyone, I know it was done in the past.
Yes to all of this, except the pet spotlight.
The judges are already over their heads with the current submissions, I don't think adding to their load is a good idea.
You could link it to a meta achievement - get certain pet achievements (and I fully agree that the spotlight should NOT be included in that list) and get 1 pet slot reward. You could have 5 tiers, or 2 or 3 or whatever. So you get extra slots based on how much work you put on your existing pets.
In loving memory of Need posting achievements?Then join Posting Frenzy Achievement Items - searchable list List of Borders and cutouts New at Fresh and Flavorful Ping Group
I'd love more unlockable slots. I know free slots might be bad for numerous reasons but I can always use more slots and unlocking them for dedicated playing would be really nice. :x
They do want people to be on the site more, so restocking, training, feeding pets, all going toward unlocking more pet slots with a maximum of 5 gained through that kind of questing sounds cool to me!
Support for anything that gives more slots. Free base pets, easy to earn, buy with sP, anything would be welcome.
With Neopets dying this is an excellent time to rope in hoards of new players and keep Subeta from following suit and croaking. Neopets users are used to have 20 pets for free, but they're very inconveniently spread out over 5 accounts. We begged for years and years and years to let us combine our accounts into one so pets (and other things) are easier to access, to give us more slots, etc. But TNT never budged, aside from that one pet slot from premium that's insanely expensive and auto abandons one of your pets if you ever stop paying.
Subeta doesn't even come close to the amount of pet slots you get on Neo upon joining. If you bump the free slots up to 10 that makes the site a lot more appealing, even if 5 are unlocked or earned with sP. Getting 15 slots with a GA would push Subeta a lot closer and help encourage Neo refugees to stay. We're used to having a lot of pets and its no fun to go from tons to barely any.
Tumblr is full of Neopets users urging their friends to come to Subeta. This is a great opportunity that really needs to be taken advantage of. A fresh crop of bright-eyed users eager to participate and play (among other things...) is desperately needed.
I'm going to ask people a question.
On other petsites that are not Neopets, Flight Rising and Misticpets, how many pets do you get upon creating an account? Like, things like ChickenSmoothie, Aywas and the likes? I never played these, so I have no idea!
That would help me a lot in calculating things!
I need more pet slots but I can't afford buying any. I have no money to buy my meds or food, either.