Buff Ward Trinkets/Nerf Duskblade's "Blackout" passive.
Now, I'm not an assassin main, And i Cant Speak about the effectiveness of Blackout,
But for the most part, The fact is unless you get a support item, Spend 75 Gold for a Control ward, Or you're any champion who Basically Has a ward ability, You're going to be down a ward at all times.
A good example is my last Yorick game against a pyke.
After a while, They got a Duskblade, And so i'd ward River bush or the top bush closest to my tower, He'd walk over there and clear the ward. 120 seconds later, I'd ward again, He'd go clear it.
And, I dont know about You Guys, But i dont like losing my ability to ward, Especially up against a champion like Evelynn or, In a different game, Talon.
So, My suggestion/s is to do one (Or more) Of the following:
1: Nerf Blackout's Cooldown. Considering that the Classic Ward Trinket's CD is 240-120 seconds, And that Blackout's CD is 90 seconds, Unless you spend money on control wards (Or have Klepto and luck your way to having a cluster-fuck of wards), Everytime you get a ward down, They can go clear it, And unless you're far ahead that you know you can 1v2 the enemy and the jungler, Its going to be a passive game.
2: Buff Ward Trinket/Bring back "Greater Stealth Totem" or Sightstone
Lets be straight here, A lot of people miss sightstone, And i dont know about you, But taking support items Top or Mid are Not Ideal, Especially ones like Relic Shield, As you'll rarely get a charge off in a solo lane.
And so, Why not bring back some blasts from the past? Greater Stealth Totem gave a 180 second ward on a 60 second CD, For the price of 250 gold, And replaced the normal trinket. Sighstone, For those that Dont know, was the pre-cursor of the current support items, But didn't have that annoying-ass quest. It offered 150 health, costed 800 gold, And everytime you backed you got 3 charges.
I think either of these suggestions would be a great way to fix the problem, As well, Being honest, Having good warding practices dont matter if someone can waltz over and delete the results, And its hard to make habits if you cant practice them.