Truth is... the quality of the game is largely going to be centered around its competitive viability. It's an FPS game. It's not competing against Angry Birds or Simpsons: Tapped out. It's competing for the dollars of the hardcore gamer.
Having sprint or Spartan abilities doesn't have to make the game any less competitively viable. A game needs to be first and foremost fun and enjoyable to play. Though that's not to say being competitive and fun need to be separate.
Lets look at sprint. Sprint damages CQC (the absolute most important part of Halo combat), it damages map control (the most important part of an arena FPS) and it damages predictability (the most important part of a quality game).
CQC is not the most important part of Halo combat. While map control is an important part of Halo (which I don't think is even technically an arena shooter in larger modes), sprint doesn't have to damage it. Predictability within your own ability, is the most important part of a game. If I can just predict everything my opponent is going to do that is boring. Where is the fun in playing something predictable? I'm not saying having everything be random is any better though. I am just saying there is a balance that needs to be had.
Add in AA or spartan "abilities" and what happens? You now have a game where you optimally play from range, where your ability to wield a gun up close isn't the major part of the equation and your positioning relative to your opponents is rather meaningless.
The game has guns. You SHOULD be firing from a range. If you get into a firefight within a tight space it should be up to the best player to win. The best player is the one who utilizes everything they have to win. Strafing, jumping, ducking, and weaving are all a part of this but unfortunately aim assist and bullet magnetism get in the way of that. Being able to sprint away doesn't hurt the gunplay either.
What does this effectively do? Kills the competitive viability of the game. If i walk into a room in CS or in Halo 2 with an SMG and see an enemy with his back turned to me, let's just pretend assassinations didn't exist for this example)... i could start opening up on him and KNOW I will win. I know the odds of me surviving and succeeding in that engagement are so high that I can do that. Throw in sprint and an AA, that predictability goes out the window. He could quickly sprint away, drop a bubble shield or whatever or healing thing and he could turn the encounter around from a guaranteed loss to a possible win. What the hell is the fun in that? His spatial awareness in this case should have been his downfall.
If you get the jump on a guy in a room and KNOW you will win, having sprint in the picture doesn't change that. It is a variable you would take into account in that situation. We don't even know how the Spartan Abilities work either so for all you know they might do nothing at all to your odds of success. Even with sprint in Reach and 4, if a guy had sneaked up on me and started shooting, I most likely would die. Even if I started running I was dead.
Now because of that, approaching someone is now risky... he can sprint... i can't chase in a tight map because that opens me up. I dont know if he has powerups. I dont know what perks he has. Even if they bound abilities to pieces of armor to illustrate the dangers, it still has no place in the game.
Risk vs Reward. That makes combat interesting. If there is no risk that takes away thrill and Halo 5 so far is still about even starts since Spartan abilities are something everyone has and sprint (assuming it's in) is would be no different. You shouldn't be able to easily predict your enemies locations. You should be prepared for it and have an idea of where they likely are. You will KNOW what they have at their disposal just like in previous Halo's. They have said nothing to indicate that abilities would be tied to armor or that power ups are even a thing.
The more shit you add the less appealing it is to watch, too. You simply can't properly convey that information effectively to the opponent, let alone an audience
Are you kidding me? If you go too far in either direction it will become boring due to it being too simple or it will be a clusterfuck because there is too much going on. Sprint and 2 or 3 Spartan Abilities are not going to do that. Look at Titanfall. The actual matches are quick, full of movement and abilities, Titans, and quick triggers. It isn't hard to follow though due to how they implement it and tie it together.
What 343 should do is nail the basics and do a total revamp of the AA and weapons sandbox.
So what about AA? What should be done with them? Make them skulls on maps, of course! you pick it up and you get an extraordinary ability with the sacrifice to your ability to fire a weapon... but this way... you defeat a skull carrier and you can then grab it and use the ability as you please. It then rolls over into a power weapon/map control thing but fixes some of the downsides to the old powerups and AA.
They are already revamping both. We have no idea what is going to happen with the SP which are fundamentally different from the AA because they are something everyone has, not some option you pick at the beginning of a match.
Just having the abilities on top of the sandbox screws with balance in the end because they aren't inherently balanced to begin with and there's really no effective way to do it. Just ends up feeling like a bastardized class based shooter in the end.
Having the abilities incorporated into each players arsenal already helps to balance them. How well they actually work is ultimately dependent on the power they bring with them.
And just for the hell of it: Copying things like call of duty makes no sense. Call of duty fans wouldn't want to buy a codified Halo. They already buy COD! If Halo fans wanted call of duty, they would buy that instead.
I agree with you on this. However CoD doesn't own sprint nor does it do anything like Spartan Abilities.