Quick Question @RIOT: what does having two damage types do for league of legends?

The only thing I can think of is that it makes it possible to be durable against some of the champions on the enemy team without being durable against all of the champions on the enemy team.

But this effectively implies that teams that don't have a good balance of the two damage types are at a disadvantage because defensive items are tuned with the expectation that you can't just build 6 magic resist items; so if you have only magic damage or only physical damage in your team comp, then the enemy team can make better use of the defensive itemization that they otherwise would be able to.

So as I see it, having two damage types theoretically provides more depth in each game, but reduces the possible variety in team comps among games.

Of course I may be completely wrong with this assessment, and this thread is meant as a question not a statement. So am I far off, or how does it work? Do you think it is worth it, do you have any evidence that it is worth it or a gut feeling?

Couldn't you imagine a league with the same depth but with a single damage type, perhaps by having defensive items that target specific champions on the enemy team, or through more active defensive effects like exhaust?

I just want to know your thoughts and your thoughts on how you thought about those thoughts.