My smaller MTBs sure feel more sprightly. I have everything from 15-18"

My 15" with a 56cm ETT just rails corners but can be a bit of a handful on downhills.

My 18" with a 56cm ETT does pretty well also but just doesn't seem to do as well in the air and is a tad slower in tight turns. It may be primarily psychological or it may actually make an actual COG difference having the top tube and seatcluster moved down 3".

Then there's my 18" with a 60cm ETT. It's kinda sluggish in some respects but it performs the best on rough downhills.

All three are completely rigid.