There are certain things in the Bose 901 design that are desirable, especially crossoverless full-range drivers and an array designed to interact with the room. There are many speakers designed to interact with the rom to good effect. Examples include omnis from MBL, Ohm, Mirage, and Duevel, bipolars from Def Tech, and dipoles from Quad, Alon, Martin-Logan, Magnepan, and others.
There are other things I don't agree with. For example, Amar Bose arrived at an 11/89% ratio of direct-to-reflected sound based on his measurements of Boston's Symphony Hall. The thing is, Symphony Hall is one of the most reverberant concert venues in the world. Mirage, on the other hand, has over 25 years research into psychoacoustics and they arrived at a 60/40 ratio of direct-to-reflected sound for their Omniguide-based speakers. I've been living with a pair of those for nearly 4 years and still find them to be engaging and timbre-correct.
I think the Bose concept could be a lot better than it is in the 901 format. Bose has improved their 4" driver somewhat over the 43 years they've been in production, but they could do better. GoldenEar's 4" driver has a cast frame and is light and fast enough to have usable response out to 20KHz. What if Bose made a floorstander with GoldenEar-quality drivers backloaded with a transmission line? What if there was a curved front baffle to angle 5 of these drivers for optimum dispersion and 4 drivers on the back for ambience? With a light, fast driver and transmission line loading, the active equalizer circuit wouldn't have to work so hard and would presumably be less intrusive regarding phase relationships and whatnot.
That said, I have to admit that I haven't listened to 901s for a long long time, and certainly haven't listened to Series VI, so I have no business saying exactly how good or bad their current product offering is. For all I know they've made significant improvements in how resolving and how wide the bandwidth is in their 4" drivers, but I don't know. The current driver still has a stamped frame and the cone material is still blue paper like the Series III as far as I can tell. They've evidently improved the baseline bandwidth, however, because the current active equalizer isn't compatible with Series I-IV.