I agree, and that's a great thing for progress on the harmonica
In this vein, here's another slide-diatonic tuning idea (actually two related ideas), prompted from a post by Suyash Kumar on the Facebook Harp Repair group.
He demonstrated how you could get really strong overblows by lowering the pitch of the slide-in draw reed a semitone (to the same pitch as the slide-out draw), and taping over the slide-in blow reeds. (The same principle applies in reverse for the top octave in Richter tuning, if that's what you like to play).
My friend Andrรฉ Coelho showed me Suyesh's demo video, which shows very pure overblows:
https://youtu.be/XNJd8k8pzBM?si=NSNFJwGTMQXjsgJx
Nice! However, hearing this made me think of an idea along the same lines that I think is better - and doesn't require any tape
It's better because it won't lose any reeds, will still give you fantastic overblows - AND will allow you to play new, beautiful bigger draw bends!
Take hole 4 as an example on a C harp. Retune the slide-in notes to D draw and B blow. Then give the blow reed zero gap, so it doesn't sound. It's now working as an X-Reed.
This way you will get a strong overblow, but also a deeper draw bend from D to C.
The overblow might not be quite as pure as with taping, but it will still be very strong and controllable - much better than with slide out.
Do the same with the other holes except hole 1, which will still need the tape. In the middle octave of C Richter, hole 5 slide-in goes down to D#, hole 6 slide-in drops to F#.
On blow breath with the correct embouchure, the slide-in notes will now work like overblows on the AsiaBend. I made a video demonstrating that a few years ago (explanation starts 2min in):
https://youtu.be/8TdkBflwKPg?si=RCE7ENXXAd5o-oh_
Instead of losing a bunch of reeds by taping them over, now you can have big bends on all your draw notes. In middle octave Richter, bends from:
D to C, F to E, A to G.
Overdraws in Richter tuning can work the same, using the same principle. Retune the slide-in blow notes holes 7-10 lower, and give them zero offset. They now function as x-reeds. This gives you strong overdraws plus deeper blow bends.
Also, since you can choose the x-reed note, you can get whatever bend you want. So on hole 7 you could tune it to A and get the bend down to Bb.
Top octave slide-in blow bends:
C to Bb, E to D, G to F, C to A