I think maybe you would have heard a solo saxophone record at some point...I imagine Trane would have been open to exploring electronics, at least in terms of providing a backdrop for his soloing...maybe a wind-controller but maybe not. Trane was as musically curious as anyone and I'm sure he would have at least checked the new technology out.
I could definitely see him doing some more orchestral-oriented records, whether with strings or synths behind...Africa-Brass was a template for larger ensemble work that Trane probably had further plans for...
As for collaborations that may have been on the horizon, something tells me he might have hooked up with Sun Ra... via the John Gilmore connection. That would have been very interesting...
Hope nobody finds this what if talk about Trane, RIP,-offensive. If you're like me though you can't help but think about what ELSE there MIGHT have been, even as you should ask for NO MORE than what he gave...