I wrote a small book about this in one of the other threads: https://www.dual-boxing.com/threads/...ving-WoW/page2

TLDR: Rift and SWTOR are quite attractive options if you've never played them before, but they're unlikely to sustain your interest indefinitely. Neverwinter is potentially a lot of fun, but they recently broke an important part of the multi-boxing apparatus. FFXIV is a great game, but not an attractive game for boxing. Multi-boxing GW2 and DDO is a totally different experience to WoW, and might be interesting to people looking for a real challenge.