I know Centercode is the place for feature requests. I have an account there, but I'm not sure if you can post feature requests there without actually being part of the beta-testing program, which I'm not currently. Anyway, in the meantime this forum at least offers an outlet :)
The new integrated Splice preview is nice, but the minimal rhythmic options (only repeated bars or single subdivisions) makes it hard to preview sounds that typically use more complex rhythmic patterns, like 2 and 4 for backbeats, every other 8th for hats, or irregular rhythms for D&B-style kicks. Even the addition of '2 and 4' and 'up-beat 8ths' options would make it much easier to preview e.g. claps and hats. Presumably this would be a relatively easy improvement to make, since we're not talking about a major architectural change.
That aside, the previous Splice Bridge device still seems superior in that you can preview samples in the context of the actual mix, which you can't do with the new integrated preview. Also, with Splice Bridge you can use delays to create rhythmic patterns like 2 and 4, which you can't do with the new integrated system.
I've seen two posts about this (a post of mine here, and one on r/ableton), but there's been no comment or discussion other than the original posters, so I'm getting the impression people aren't using the preview feature much, or aren't finding the absence of common rhythmic patterns like '2 and 4' to be a problem. But, it still seems like a reasonable improvement that could make the feature much more useful.