I think this would work fine. The current design is less intrusive, avoids
code duplication, and would immediately work with a "new" KSP that required
estimates. But I think you are correct that the user interface with
-ksp_chebychev_estimate_ is simpler and thus preferable, even if it has no
less
It seems to me that KSPSPECEST is a pre-processor for Richardson and
Chebychev that computes "good" parameters using either GMRES or CG during the
"first" solve.
So why not make the user interface more reflect this, for example:
-ksp_type chebychev -ksp_chebychev_precompute_parameters
