That is the same circuit as the ETI/Frisby with one or 2 minor changes. Having used this crossover for a long time I think it can be bettered, and I'm keen to try Eschenborn's modified Concerto crossover when time allows.
Before you try a new crossover, decide whether the problem is voicing (tone) or blending (the actual cross). This is important knowing the way forward to give you peace of mind.
Do this by trying to EQ the speaker. If you can fix the issue, it is a voicing problem and you should hold the relative driver contributions the same when you make changes.
If you are unable to fix the problem with EQ, it is a blending issue. The relative contribution of the drivers needs to be changed. This comes down to phase, overlap and also about issues that only one driver suffers from. After that, repeat the EQ test.
Do this by trying to EQ the speaker. If you can fix the issue, it is a voicing problem and you should hold the relative driver contributions the same when you make changes.
If you are unable to fix the problem with EQ, it is a blending issue. The relative contribution of the drivers needs to be changed. This comes down to phase, overlap and also about issues that only one driver suffers from. After that, repeat the EQ test.