Buff Karthus or Rework?

As I have noticed in the last two seasons, has been a little bit on the weak side. Being countered by almost every mid-laner and his ult being countered by pretty much any champ, item, or summoner spell, particularly and . These summoner spells come around very often because of their sheer value making a little more weak in certain teams.

Pretty much every champion now a days have some sort of escape or CC move that can easily kill or move away from . In addition these champions have a much better power creep early, mid, and late game while is mainly a late game champion. As I have been seeing in this season, late games are becoming a little less common, depending on the type of teammates you have, etc. Even when reaching lategame with , you can see that the only thing you are really going to do is Ult, and that's pretty much it. He is easily blown up and outplayed because of his lack of direct spell casts such as , , etc. You might think "Well, he has an AOE E, that is instacast and his Q is on a really low cool down with low mana cost", well you see that is fine and dandy, but actually landing these on anyone who isn't slowed by 's E is pretty hard to pull off. The only way I can see someone pulling off these spells is if you are really good at the game and especially with .

Now please do not hate me on this, I am just pointing out some flaws with at the moment, anyways here's what I think could be done.

R: Requiem. Should have a lower cooldown due to the fact it has a lot of counters. Probably like a 100/90/80 CD.

W: Wall of Pain should remain the same, but with some tweaks. If a champion was to get hit by the Wall of Pain, casting a Q in the Wall of Pain would make the champion automatically hit by the Q. This could be broken, so balance could be made.

Lastly, his E: Defile. I think the E the longer it hits a champion, like let's say 3.5 secs while an enemy champion is inside Defile, it should stun them. Not being able to be stunned for 5 seconds after the stun.

Or Riot could Rework Karthus, making him up to date with his kit and making him a little more strong.

PS Riot: There's a bug with Karthus' Q when in Death Defied, it will look like he can shoot his Q twice, it's kind of hard to explain...

Please guys let me know what you think, this is just an opinion.