You won't regret getting into DotA/DotA 2. That's all i'm going to say about that.
Skasi: I highly doubt said AoS maps show(ed) the level of balance we see since Icefrog's days. Also, 6v6 in WC3 is only possible without observer slots, which were/are sort of needed for competitive gaming. I mean, I don't claim to have an absolute overview over all AoS-like maps (SC 1 was before my time... But thanks to the awesome map editor for wc3, basically everybody with half a brain could make one there. The numbers of those speak for themselves...), but I'd very much be interested in seeing one that features better balance than DotA 3 years ago (seriously, 1 year only? The second International was already over then!) or a hero more complex than invoker (or old invoker?). Note that both uniqueness and complexity can also be negative, if done wrong. :P
I pretty much despise all the "pay to unlock/play heroes" moba versions. You actually pay to play a dumbed down version of the original(s). Makes no sense to me. Yeah, scratch what i said earlier about "that's all", but DotA 2 is as free to play as it gets (and we have some very narrow views on what qualifies as F2P around here, apparently).
1v1 is simply not balanced in a game that was made for 5v5 (well, talking about DotA here, but applies to other mobas, too). If you were to make them all at least sort of viable in 1v1, you'd lose so much variety in terms of possible concepts. I mean, the entire idea of a support hero revolves around helping
other allied heroes in getting their job done.
Unless the matchup is either determined beforehand or a mirrormatch, you would also have blind pregame RPS.
All of this doesn't prevent 1v1 tourneys from being organized and both fun and interesting (1v1 still remains a great display for skill and consists of elements that are all vital in winning mid in a 5v5), but unless you design the game around it, it will remain niche.