Alright well, as you described, Overwatch is a completely different game. Less characters with more maps and completely different objectives and ultimate charge rates.
League is a game centered around 3 things and 3 things alone:
- Experience
- Items (gold)
- Objectives (and buffs)
There are 3 ways, generally speaking, to shorten game length on a macro level (aka, ignoring specific champion balance):
-
Make experience scale faster
what this causes is whichever team get an early lead will accrue experience at an exponentially faster rate than the opposing team. If you look at the recent jungle changes, you'll see that this is quite a touchy means to fidget with and generally ends poorly for game health.
-
Increase gold income
Now there are different ways to do this, but those don't really matter. What this does is a few things. 1, it generally fucks with balancing because it lowers the window of time early game champions can impact the game which means a hypercarry meta will emerge. This usally means 2 hypercarries, think Azir/Kog, followed by an enchanter support and 2 tanks. It's generally not fun, but I'll get back to that later.
-
Decrease # of Objectives (not possible unless you change the actual map) / Decrease strength of objectives
I'll touch upon the 2nd part because the 1st part isn't feasible. Decreasing the strength of objectives (i.e: turret health, baron/dragon damage and health, increasing inhib time respawn, etc) is generally how Riot alters game length on a macro level. There have been a lot of baron/dragon/turret changes in the past couple years, most of which have actually decreased the game length if you ask most people (I could be wrong on that though).
The problem with this method is that objectives are inherently tied to gold. Whichever team gets those towers first gets an income of gold which translates to items which means more objectives. It snowballs which means there will always be an item disparity.
Now there's a secret 4th option that occurred to me while writing this, and this is probably what you're thinking about. Lowering the stats of items and making champions more kit-reliant.
This wouldn't work because now you've effectively robbed the winning team of their lead. The game simply can't end in a short amount of time if the teams are constantly at similar power levels. This also fucks with balancing as a whole, that level 10 toplaner now has a vastly higher power level than that lv.7 adc, despite them having similar items. Changing items like this would require a top to bottom change for every champion in the game.
Also note: I hope this didn't seem brash or rude, it's just 2:30am and I just stayed up a lil longer to explain this. Imma go pass out now :^)