Well put Rob.

ALL TECHNIQUES SCORE EQUALLY*
*with the caveat that they are on target and show effect.

You (as a judge) need to see effect, whether through losing balance/composure or the fighter being kicked getting frustrated or consciuosly pulling away from a technique, as if they are scared or concerned about the power of the shot which is landing.
The reddening of a leg (or a lat) shows that the kicks have power, but if they do not move the kickee (rather than kicker) then it has minimal value.

OK..... a little test
If two fighters face each other (low-kicker v body kicker) and lets the other fighter just land a technique without blocking, who is going to be the first to give up.
If the low kicker is accurate then one on target will disable an opponent
If the body kicker is accurate then one on target will disable an opponent
For a low kick to be bang-on target and have that devastating effect, you are probably looking at a target area about 10cm in diameter on the side of the leg.
For the body kicker to be accurate, he has a target area about 40/50cms in diameter, so by this rationale the body is an easier target to hit. And I think this is why people are seeing it as "body kicks are best" because its an easier score (relatively).

If people are trained not to be scared of a technique then the criteria lies with balance, and how far people are moved by shots landed.

At the end of the day its a fight.
The stronger (more effective) guy wins.
Look at it like a street fight....if guy bashes guy B for 5-mins and then guy B comes back and leathers guy A in 2-mins, who wins? Guy B, cos he has weathered the storm. Guy A couldnt finish the job and burnt himself out, and guy B still had enough in the tank to step up and take the win. The only difference with muay thai scoring is that its in the ring, with a ref, over a specific time.....this is why timing a performance is vital and more emphasis is put on round 3 n 4 (money rounds).

As for Anuwat. I think it would be stupid/naive to think that he is a one-trick pony..... its just that he is renouned for his boxing. He has had a lot of KO's through punches, and we (in the west) tend to recognise the effectiveness, due to the heritage (Marquis of Queensbury). Anuwat also knew that Liam is a prolific puncher with a lot of KO's on his record.
Punchers need a base to land their shots, and if that base can be broken (low kicks) it takes the power away. If you body kick against a uncher, its a dangerous game as you may get caught halfway through a kick, and totally lose balance (which, as i was saying earlier is a big score), so Anuwat utilised his low kicks to break liams balance and sap his power.....therefore a big score.

This is IMHO.....
No one will think bad of you Steve for asking a question, as I dare say there are loads of other thinking the same thing..... this is just how I understand it anyways.