What you sacrificed a little of that tankiness for a little more movement and/or damage? I bet she might be a decent top laner or even jungler given just the right tuning.
Probably not, high durability is at the top of the list of things that should be true about Rell. If Rell becomes a somewhat niche top/jungle with our efforts to serve support Rell that's fine, but we don't have plans to intentionally support those roles right now.