There needs to be some sort of comeback mechanics pertaining to vision
One thing that often isn't thought of is that when a team gets ahead, they don't just get more gold, experience, items, etc., but also get much more vision control. We've all had those games where the enemy team gets ahead, and suddenly your attempts to ward become suicidal because you'll frequently get ambushed. Every single brush becomes a potential deathtrap, and this leads to farming becoming dangerous, which further exacerbates issues. You could always go with the blue trinket, but that's not nearly as good as placing regular wards since you won't have vision on the targeted area for long.
Unfortunately, while Riot has been tuning comebacks in terms of gold and experience, they haven't done anything that might pertain to vision comebacks. Intel is arguably far more valuable than power, but those who are on the losing side tend to continue losing out in that regard. And before you say "comeback gold means more red wards", that's stunted by how you can't carry more than 2, and can't have more than one in play at a time.
Coming up with mechanics that allow for "comeback vision" is tricky, but one thing I can at least think of is the following:
When you die, your trinket's cooldown is reduced by a percentage. This percentage is much lower if you were on a killing streak, and higher if you weren't doing well.
While this might sound like a "feed more to get more vision" approach, remember that you'd still have that 3 ward limit, and that intentionally feeding the enemy just to get more wards is a surefire way to get you permabanned. The idea of the mechanic is for your trinket to cycle its cooldown faster if you're dying a lot. It's not a perfect system, but it'd be a starting point.
In any case, I'd really like for there to be comeback mechanics that pertain to vision control. It's really demoralizing when your enemy gets ahead, thoroughly wards your jungle, and then you can't even try to clear them out without being ganked.