Backhands
 

How skilled is a player when they can hit both a one handed backhand and a two handed backhand with ease?

It probably indicates a good amount of experience, but it isn't a good thing to measure skill. I can hit both with ease and so can my club's coach. Do we both have a good amount of tennis experience? Yes. Does this mean I'm at the same level as a pro? Nope.

Likely a pretty good player, but does not indicate a level.
He may still lose to 4.0s if his game is not overall to that level.
How is his Fh? and against who? Good strokes don't look as
good against better opponents.

IMO, skill is only important to the extent it is employed to win matches.

Mid+ 4.0 is the worst player I have seen with at level strokes. At 5"2 he only used his one-hander teaching and in during practice.

chances are if you can hit a good 2h bh then you can probably hit a decent 1h bh and viceversa but it doesnt indicate any kind of skill level cause they could have just practiced it a lot but the rest of their stokes might not be as good

Tsonga is the most talent player in the world. Poweful bash of a 2hB and precision laser 1hb passing shot.

Skilled?
No, how about adaptable. Now the player has to decide which to use.
Can't use both, as it doubles the learning time. Time better off spent learning another stroke at it's application.
Keep both now, use the one you like most of the time.

Federer can hit a good 2hbh topspin backhand.
Nadal hits a nice 1hbh TOPspin backhand.
I'd bet DJ and Murray can go both ways too.

I'm a 4.5 and I can hit both about equally.

I have seen very few players 3.0 and up that CAN'T hit both 1h and 2h back hands in some form or another. most players have a slice in their arsenal, which is almost always a 1hbh, even if their topspin groundstroke is a 2hbh.

I have a 1hbh for my TS groundie, a 1hbh for my slice, but since a 1hbh takes longer to setup, sometimes I don't have enough time "get there" and have to resort to a 2hbh.