Firstly, you are absolutely entitled not to find TPS fun. I always thought that TPS was going to be what was called, in ye olde dayes of gaming, an "expansion". It was and, in that context, I thoroughly enjoyed it. However, be careful giving away your money for a BL3.
I've been following Battleborn over the last few months and I've lost count of the "don't do this; make BL3" posts. It doesn't seem to occur to anyone that GBX may not be able to make a game as good as BL2 again. Think of all the franchises whose later games never quite equalled the early one that got everything right.
I have read (unsubstantiated) reports that Valve are not concentrating on an H-L3 because they may not be able to come up to expectations and if their offering is anything less than genius, the Internet excrement-storm could actually harm them. It could be the same for GBX and BL3.
I have thousands of hours invested in the BL franchise, so I'd love a better-than-ever BL3. But that can't be taken as read. Don't bin TPS yet. It may turn out to be better than you think