Pokemaster should post an answer after I do when he has the time, though I think I have some sort of idea of what his answer might be, for the time being.
One thing is for sure though, and that is the wall post limit isn't going anywhere. Indigo mentioned in the comments that it helps block spambots, but it is also helpful to stop real people from mindfully and maliciously spamming wall posts to clog the site and create a chore for whomever they wish. Limiting wall posts makes it a lot harder for people to create a problem before somebody does something about it.
With that said though, I do understand your perspective that the wall post limit is a bit restrictive. Whilst I've never had to deal with the limit of 5 posts per hour myself, I can see how it might be inconvenient to people overall. I don't see the harm in bringing the limit up to maybe 10, though Pokemaster might have some further input as to why the limit is at 5 in particular. Changing this is a simple as updating a number in the admin I think, so if you're unhappy with the wall post limit, I'd be discussing what number would be best first of all.
Lifting limitations to your own wall could be opening the door for bots to make accounts dedicated to spamming their own walls with stuff and therefore using PokeBase to boost their search rankings (as is their goal most of the time), though I think the problem here is more to do with the fact there's no way we can remove wall posts without intervention from Pokemaster. But regardless, any type of change with your own wall would have to come with a full update to the software, I don't think there are any options for changing this in the current release since we'd probably have them in some form already.