The geometry that fits you best, wheel size be dammed. Look at the fit first, then wheels. I'm 5'4" and ride solely 29er - went for the fit first with all my bikes. Transitioned from 26 two years ago so we weren't bringing as many spare parts to 24 hour racing. I didn't have too many issues, but the 29er did require more body English in tight spaces.
Sluggish handling can also be more a function of rake and head tube angle then wheel size, so that is something to think about. The xc bikes (epic) will have a steeper head tube angle so will handle crisply when compared to trail bikes (stump jumper). If you want a bike for riding, fun and racing, I would seriously consider the Specialized Camber - regular model has 110/110 and is playful. The Camber Evo has slightly different geometry, do look at the charts. It's also 120/120 - can do both xc with slight penalty and trail easily. I rode a small camber Evo at the Vapor Trail 125 this month and it was perfect.
I would counsel against 1x11 - not sold on it even after racing an entire season with it. I have 30 front chain ring. The 2x set ups are better for the mountains around here - IMO.
Good luck, have fun shopping and test ride as many bikes as you can!
Vale!
Tracy T
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