B/W 702 s3

B&Ws are known for bass. The 702 gives the 802 a run for the money, especially in punch. Punch is bass above 40Hz. But two subs will give you better results than another amp for about the same price.

Likely you have bass suckout in the 60Hz region. Many rooms have this. Subs can help to fill it.

These are pretty much out of the box measurements on my 802D2 and DB1D for music. The 802 was calibrated to minimize cancellation below 40Hz but the curve is the same out of the box elsewhere. The 802 gets decent output to 18Hz. The sub extends it to 8Hz. Calibrating the sub removes the 2nd hump and partially fills in the suckout from 70-100Hz. The 702 should probably get you to about 25Hz but feels more tactile above 40Hz because of the smaller box.

I had a pair of DB4S but you need at least two to get satisfactory output (for music) in a living room. Four would have been ideal. Sealed subs are best above 30-40Hz. Ported better below 30-40Hz.

https://mega.nz/file/7ExmzKzQ#uPb0-IEE9MOgLsMYxbjF1y1yjw-tTAjirY-28HvSoa4

Have you taken any in room measurements to see how the room is affecting your speakers?  That might be a good place to start so you have a baseline relative to your listening space.  REW is free software and a decent mic costs $100.  Cheaper than springing for new stuff that might not fix your issues.

What do you mean by "average"?

Can you be more specific?

My B&W 803 D3 needed lots of changes to speaker and listening seat position, and also two subwoofers, before they sounded the way I wanted them to.

I have the 703S3 and I went through a few amps before I liked the sound of them.   I agree with you they sounded “ok”.   One day my buddy brought his Macintosh amp and they sounded totally different.   I ended up going with a Passlabs x150.8 and they sound awesome.   B/w speakers need really powerful amps to sound good.   Powerful I mean high current.   Don’t think the Rotel is doing it for you.  I later added two Rel subs and they sounded even better.   Having said that the pass labs had them plenty of bass.  They subs just increased the sound stage. 

I had a similar experience with my Martin Logan 20i - they sounded just "okay" and no "punch".  So, I've decided to sell them - and moved them into a small room and temporarily connected to a vintage Pioneer SA-9800 (100 WPC).  It was like I got an upgrade to a much better pair of speakers, and I actually still have them to this day. 

In summary - I would say a more powerful amp and some full-er range speakers should solve all the issues - and we only live once.