Wrapping the multiplayer in fiction doesn't have an effect on the gameplay - bad design does. There's no reason a competent developer can't have the gameplay be balanced and fun and rewarding while being tied into the mainline story. It's not the idea that is as fault, it's the execution. They didn't HAVE to have maps be filled boring UNSC labs and brown rocks despite being set in a holodeck that could conceivably generate any wacky setting they desired - in this way, having it set on a holodeck could actually be creatively freeing in that they are not bound to any set of environments; they didn't HAVE to have said holodeck generating random weapon drops. They CHOSE to do that. You have to question what was the thinking behind choosing to be boring and random? Maybe it makes more sense to have the Infinity generate combat environments the Spartans are actually likely to find themselves in - war happens in "real" places and there is probably a lot that can randomly happen in an actual skirmish - and this line of reasoning possibly helps rationalize shoehorning in gameplay elements from other games that have no place in Halo for the sake of chasing trends and catering to the lowest common denominator.
The Infinity holodeck could just as easily be said to generate Midships and Sanctuarys or planets made of bees filled with trees dangling with baby elephants. Maybe nobody thought to do that though.
The Infinity holodeck could just as easily be said to generate Midships and Sanctuarys or planets made of bees filled with trees dangling with baby elephants. Maybe nobody thought to do that though.