Very useful, thanks!

Great Questions!
1 ) LOL and SL’s F2P model is very different. LOL could easily get enough depth out of 17 characters because each character is very unique (so many different abilities, tactics, etc). SL is trying to make money off of progression, and that can’t be solved by simply adding a few more heroes or pacing the game to be a bit faster. Eventually (in my opinion) they will run into the same issue. I would still recommend that they change the system to more of a Gatcha, or find a way to make upgrading and deciding between heroes to be much more deep with another system.
2 ) Yes I think its very possible to have more stats in SL. Personally I think “casual v core” & “east v west” is not a great way to understand the current marketplace. Its far more complex than just those 2 dimensions. There are a number of games that have more stats that SL including the recent Marvel Contest of Champions. Ultimately the goal has to be creating long term retention, not creating the widest possible audience. This can come through a Gatcha system, more stats, and increasing the value of stats. There are also a number of other avenues that are more approachable, but will (usually) require on substantially more content and variety.
3 ) Haven’t really thought too hard on the size of the arena. It could be a relic of keeping the arena small enough to fit on all devices, it could be because of balancing. I’d assume Supercell have done their research on that, but it would be worth experimenting with if you are working within this genre.