Basically every champion needs them; nearly every player buys them. Why not give boots their own designated space so that people could have another item option? It would be slightly different for balance, but at least that way it doesn't seem like everyone has to waste a spot to carry the same item type into battle when they could have six other things, the trinket and the boots.
Effectively, you're suggesting seven item slots.
I'm not sure you realize just how broken the game would be if you did this. Remember, each damage item scales multiplicatively with every existing item in the inventory. It's a gigantic increase in damage that will break tank/carry balance, towers, barons, dragons ... you really really do not want what you think you want.
I agree with this idea.
You do realize that this makes life even harder for the majority of supports and tanks? ADC and APC being able to squeeze in yet one more full damage item alongside a single defensive item leads to a lot more damage than you'd think given the multiplicative nature of AP with Deathcap and AD with crit, crit damage, and attack speed. And both penetrate defenses too well... have fun being the support or tank when both carry types can smack you for an extra couple hundred per action at a moment's notice.
I agree, but they won't, because it creates "strategic diversity" or some other BS to have it as is. "oh, do I need boots? or do I need that item slot for something else for this back?"
Personally, I'd do away with boots and give every champion a scaling MS stat throughout the game as they level, although that would likely make certain champions (Blitz) a serious pain since you can't purchase the boots to get the MS to move faster to avoid the hooks... what do?
scaling movement speed with level is not a good direction in my opinion. that either keeps everyone on the same level, changing nothing but the pacing of the game and making skillshots generally less useful as the game goes on, or skews the game even more towards the winning team.
The difference between trinkets and boots is not every player used wards come late game. "Oh, I have full build? Can't buy wards, I guess." This was especially true in the era of "only the support buys wards." If I recall correctly, trinkets and the 3-per-player ward limit were added at the same time, which largely did away with that meta; trinkets were created to relieve supports of having to do all the warding.
Now, what does introducing a "boot slot" do? It lets you fit an extra item in your inventory. This is... meaningless early game. Mid-game, it might let you keep an extra unfinished item in there, maybe get some wards you wouldn't have gotten otherwise. Late, it's just a massive powerspike. Do you really want to see ADCs with IE/Shiv/Bork/BT/LW/GA and greaves too? Or APs with Morello/Deathcap/DFG/Zhonyas/VS/GA and sorc shoes? Or for our more risky players, replacing the GAs on either of them with a scimitar or rylai's/liandry's. Then there's the Bork/Triforce/Randuins/Visage/FH/Sunfire bruisers with mercs, doing craptons of damage while still being pretty tanky. Currently, there is a choice you have to make between doing more damage verses being safe. An ADC with a core of IE/Shiv/LW/Greaves can get two of Bork, BT, and GA, but not all three. If they want to melt tanks, they take Bork. If they want to murder squishies, they take BT. If they want to not die to an assassin, they take GA, and choose to murder one type of enemy a bit more softly; you can't murder everything and still not die to assassins. But, with an extra slot, you could. All this change does is promote everyone doing more damage lategame, while still retaining all their (relative) safety. In effect, this change would reduce meaningful choices, something that goes opposite to riot's design philosophy.
