you cant really measure the difference in the amount of skill it takes to play two different genres, there are way too many factors to get a good result
Ontopic though, you are talking about repetitive? Lets look at some other genres
FPSs - AT LEAST as repetitive as an MMORPG. You can change weapons, improve your skills overtime and play with different teammates. In some you can even change classes and stuff, but the beauty is that different games have different maps and weapons. Yay.
RTSs - Maybe not as repetitive as the average MMORPG, but can still at some points be quite repetitive. Often you are requires to "anti-build" or meerly have a set of units better than your opponent, but most RTSs dont have that much flexibility. In most RTSs, you select your "Race", build up a base, build units, upgrade them with the right special abilities, attack / defend base", build expansions and after a while you win / lose. Luckily there are many units to choose from and many races to choose from in most RTSs, but after a while you realise you use the same race and the same set of units until you realise your enemy is "anti-building" you, and that is when you break the "cycle of repetition"(or if you decide to "anti-build" you opponent, works both ways).
2-3D Fighting games - Oh lol, we have a winner. There is no form of flexibility to your combat style unless you switch character or decide to use different moves. Unlike MMORPGs, FPSs and RTSs, most of these games arent even patched either. And depending on if you are the defensive or the aggresive type, blocking is likely to be one of the bigger parts of your gameplay, considering if you dont block in some way, you will be smashed. Oh, and atleast there are several aspect of the other genres, unlike this one where there is only 1 aspect, and that is fighting.
Music games - For those who dont understand why this is here, dont bother asking, you should know
Singleplayer games can be repetitive aswell. If you replay the game several times, you will find yourself doing the same thing over and over again. A game becomes repetitive if you play it in a repetitive way. Yes, this is very easy to do in an MMORPG, but also in many other genres.
Thats my 8.33 Tenge