I Googled for the X-2000 reviews and have yet to find a bad one except from you (no pun intended). The British Whathifi, did say at loud volume there was some brightness in the treble but at moderate volume no issue. That is typical of what professional reviewers say about lower end amps regardless. This thing has been getting 4.5 to 5 stars in several reviews I read so far. As I said before, I have no use for professional reviews except for the test bench part.
For other reasons, I would never consider any Denon below the 3XXX (or X-4000 now) series. For Marantz, I would go as low as the SR6000 series but if you like the SR5008 imo it should be fine too. If you still don't like it then I think it is time to shop for better speakers. There are no shortage of the so called "warm" sounding speakers that could also tame some of the receivers/amps you may end up getting, psychologically.
For the time being, try DEQ with offset of 5 or even 10 for stereo music listening. That will tame the bass the treble somewhat. As for the Pure Direct, that is a myth especially for the lower end AVRs such as the models you have been considering. If that even makes any significant difference for you then you really need to do some real blind tests, and I won't say more or repeat some of the stuff I said before, to risk getting you upset.