Maybe not as much a beta as an unfinished product.
There are other great unfinished products. Schubert made some. The Corean war gave us M.A.S.H., and it's not finished. Unfinished furniture is very popular in the US these days.
Schubert is currently decomposing, and unable to finish his work.
Unfinished furniture is advertised as such.
Sometimes other people can try to finish unfinished symphonies or furniture.

RTW was marketed as a fully finished product, and also something like "the most moddable game ever" or Rome "moddable" Total War.

It was clear from looking at clues in various files that development was cut short, and from glaring bugs that QA had been ... average.

There have been several hints that CA just ran out of the time and resources that Activision had allowed them, and just had to tie up the loose ends as best they could.

I agree with those who think that 1.2 is "release quality". It is of the quality I had hoped for in 1.0

Other people try to fix what's left.
HA have already been fixed, at least 95%.
Glints and reflections are fixed.
Map extensions are available.
Completed Factions mod is available.
great Historical Battles
new Formations
a plethora of new or reskinned units
tweaks to battle behaviour, animations, killrates etc...
It's really starting to shape up.
(but it's a nuisance trying to keep track of which mods are available and worthwile due to the insane amount of TW fansites and fora)

There are too many hardcoded values that affect moddability, though. Good luck to those who are trying to make a total modification. I mean that.

After 1.2 I've started playing RTW again. I play it way too much, according to my fiancee... It's a great game. It could have been the greatest...