I suppose I can see how constraints might stimulate creativity. The fact remains, however, that removal of constraints can stimulate creativity. I played four string for 20+ years, and when I tried a fiver, the additional range was an epiphany. Breaking out of the four string box made me a MUCH better player.
I don't see the point of going back to four string on occasion just to force my brain to be creative (in fact I've sold all my fours). Likewise, I'm not going to play a 6+ simply because it provides a larger canvas/palette than five... sixers don't work for me for a few reasons. I'd rather stick with the tool that works best for me, and of course it's perfectly OK for others to do the same, whether their choice is four string, fiver, 6/7/8+, or any combination. No justification required.
I don't see the point of going back to four string on occasion just to force my brain to be creative (in fact I've sold all my fours). Likewise, I'm not going to play a 6+ simply because it provides a larger canvas/palette than five... sixers don't work for me for a few reasons. I'd rather stick with the tool that works best for me, and of course it's perfectly OK for others to do the same, whether their choice is four string, fiver, 6/7/8+, or any combination. No justification required.