I don't think flat toms are as much a fashion in themselves as they are a practical result of the tendencies for both "virgin" bass drums and for toms to be shallower than 20 years ago. It also seems like most people have caught on to the concept of back pain so they arent sitting as low.
Add those three things to a new set bought by someone used to playing power toms and I think most people would look at them and say "those don't need to be angled like Mickey Mouse ears anymore"
Standard sized toms were also available 20 years ago,as well as since the 40's,up to and including today.Power toms were drum fashion,with power tom sizes STILL available from drum makers as well as from shell manufacturers.
The consept of the virgin bass drum is also nothing new,as toms were mounted on bass drums using clamps ,since the mid 30's.Now we're just using clamps to mount them to racks and cymbal stands.
The consept of virgin bass drums being better sonicly is again,more drum re- fashion than actually decernable.I'd love to hear a blind comparison test of a virgin drum and one that has mounts attached.
It is in truth , more style than actual substance.
As far as flat toms,just as one example,Emmanule Cappalette has superb posture while playing,and nothing is flat about her set up at all.The same can be said for Simon Phillips.Just watch him play .He uses 24" bass drums and deep toms,and has excellent posture.He also dosen't seem to have to struggle to play his kit at all considering he's only around 5'6".
Posture is all about there you sit,in relation to your set up,and keeping your back stright and not reaching for everything.The whole powertom angleing thing was more about looks and using 14x13 and 15x14 and even larger toms with 24-26 ' bass drums.
I had a 12/13 power toms set up and a 22" bass drum.No Mickey Mouse ear angles were necessary.
No matter what set up you use,if you sit too high or too low,and don't have everything is easy reach......you'll have problems that smaller bass drums and flat toms can't cure.
I disagree and I still contend flat tom set ups are drum fashion,and will go the way of Chinese toms.
I'll also go a step further and say the vast majority of drummers play their kits set up since the way the've been set up since the 40's,and setting up with flat toms is greatly limited to younger players only.
If you like flat toms,then hey,what ever blows your hair back,but better for posture and more ergonomic? Horsey turd.Bangs and the foward comb are as big as they were in the 60's too..
Steve B