I know the Revels well. They do like a little power. Hegel and Luxman are like comparing BMW and Lexus. They are both nice cars but the driving and riding experience is very different.
Luxman is going to sound soft and musical yet the detail will remain to some extent. This smoother, more liquid sound is a matter of taste. The mid and treble will sound much more natural but this will come at the expense of sound slightly flabby and rounded in the bass region.
Hegel is the exact opposite. It is crisp and precise while remaining relatively neutral. This is extraordinary because usually this is accompanied by a tinge of brightness from many manufacturers. Bass will be tight and refined but at the expense of somewhat analytic sounding treble and mids.
In this ~$6 to $8K range this is the tradeoff you will make. There are many amps in this range that will be in the middle. More liquid than Hegel, more analytic than Luxman. Better or worse is a matter of taste.
Regarding impedance which is far more important than topline power, you need an amp that is comfortable at 3 ohms. Even at 88dB efficiency, you aren't using very much power at normal listening levels. It is typically only in dynamic peaks that you need that headroom and that tends to be at the lowest frequencies.
Regarding Class A sound - I have heard bright and annoying Class A amps and warm and sweet Class A amps. Output stage design, transformers, and choice of transistor matter. Don't assume because it is Class A, this it will sound a certain way. Since the transistors are receiving full power 100% of the time, Class A amps tend to be slightly faster and slightly more powerful at the same power rating vs an AB.
For some perspective though, an 88dB speaker will output 94.3dB of volume if you are seated 10' from it in a normal environment (speaker about 3' from the wall). This means for most music, you are not going to use much more than 10w, even if you are listening at close to reference levels, ~85dB as you need about 10dB of headroom for most music. 20dB of headroom is optimal and meets THX standards which for those speakers is 120w of power. Unless you like to really turn it up or you are in a big room...120w is plenty for those Revels.