Erm, maybe.
The ASR review of the 3400 showed a below-average DAC connected to an amplifier section, which by modern standards, has absolutely shockingly bad noise and distortion. It is very powerful however which makes up for a lot. (The 1120 though is not particularly powerful. )
That poor SINAD performance however is compensated for superbly by the best DSP software on the market, and what we care about is the end result.
But even in its "naked" state without RP the human auditory processing system is not up to the job of distinguishing these things very well; the transparency you mention is of course what amplifiers should be - they shouldn't actually sound like anything, they should just amplify the source accurately.
So if those tests are correct, and I am more inclined to believe them than not...
Without RP you'd be a lot better off using a Crown or Behringer amp, or either of the others the OP auditioned.
I read a rumour, can't remember where, that Lyngdorf are about to replace their 20-year old internals with Purifi boards (they are both Danish companies) which will take them from sounding good but measuring shockingly bad to state-of-the-art performance, add RP on top of that and the next gen of Lyngdorf will doubtless be untouchable.
I wonder whether they will simply and quietly upgrade the internals or produce a new line?