Want a new amp but what to get?

Sounds like you may be looking for a little more heft or meat on the bones in the midrange? McCormack amps are known for having expressive mids for a solid state amp, and as an owner of a DNA 0.5 Rev A amp I’d agree with that. Here’s a nice DNA 1 with recent Gold Special revisions that would be a big step up over your Rotel and is priced at half your $5k budget.

https://www.audiogon.com/listings/lis9fehd-mccormack-dna-1-smc-gold-special-solid-state

There’s also a very clean Pass Labs XA30.8 available under your price cap that would give you rich and expressive mids and that Class-A smoothness and liquidity. As it’s a pure Class-A amp it will run on the hot side, which might be a concern if you like to leave your amp on all the time or don’t want the heat.

https://www.audiogon.com/listings/lis9f6j0-pass-labs-pass-labs-xa30-8-power-amplifier-solid-state

Both are excellent amps that will yield significant improvements in the mids and many other areas as well, and your speakers will definitely benefit from and reward you for the additional refinement and capabilities of either of these fine amps. Hope this helps, and best of luck.

I had those exact speakers for two months. I used a Primaluna HP Dialogue premium.  That was plenty of power; the 948 are surprisingly easy to drive. The sound was effortless.  I currently have Dynaudio contour 60's which really benefit from the power of pass x250.8 (or similar). I did have an xa30.5 for some time and it was a stunning amp with incredible power margin...far stronger than 30 wpc (actually its a 100  watt into 8 and 200 into 4 in class ab)
I strongly suggest you try the Pass XA30.8 or xa30.5...you will be in for a treat.

Before you make your final decision, I encourage you to read Roger Sanders' excellent white paper (you can find it on Sanderssoundsystems.com in his Technical Papers section) titled tubes vs. transistors. I found this extremely educational.

Here’s another excellent option that’s cheaper than the others I mentioned but will make your 948s sing. Like the Pass amp it’s also pure Class A. I’d just check to see how old it is just to see when/if it might need to be recapped.

https://www.audiogon.com/listings/lis9di3b-clayton-audio-s40-solid-state

If it were me, I'd buy a Valvet amp.  Read the reviews.  The E2 is probably a little too flea powered even for your speakers, but the A1.2 should work just fine and is well within your budget new. 

https://highend-electronics.com/products/valvet-bricks-a1-2-power-amplifier?variant=31868821635