As a player, yes. There are two main drawbacks of OCs: they aren't anybody's waifu, and they can be terribly designed. But if they're well-designed, I'd absolutely enjoy it anyway. Like I said canon ponies could then be modded in as an unofficial extension, but I'd definitely still enjoy it even without that.
Legally, I'm 99% sure it should be just fine as well, exactly like the other anon has said. If you make the personalities TOO on the nose, there are laws to catch things like "Merio the spanish electrician" which are clearly meant to be "the same thing but with an attempt to have a legally distinct name", but I can't imagine that just having similar personality traits - while using original designs, names, backstories, etc. - could possibly be infringing.
One legal grey area, however, would be the use of Equestria itself as the setting, and even Ponyville. I'm not sure how that could be remedied; even if the name is never mentioned and worldbuilding is left intentionally vague, if you recreate designs of show locations (like Carousel Boutique, Sugarcube Corner, etc.), I'm not sure where that would lie legally. I suspect that if that had been all the association there might not have been a C&D in the first place, but now that the attention is on them, it sounds like a risky path.