At this rate, should Karthus just get a new ult?

The only good feature about Karthus' ult is the fact you don't need to leave lane to properly use it, but aside from that it just doesn't get the job done anymore. They are already a plenty of ways to counter it (and counting), the damage output isn't very high (only a base of 550 damage maxed), and it's pretty much useless in every game mode besides Summoner's Rift.

I've been playing Karthus since season 2 and his ult was one of the best things in the world. Your hardest counter was Soraka back then mostly. Now though we get the honey fruit plant, we get this new assassin item that channels a shield (on a 30 second CD), and Karthus is just sitting there like, "This is okay. This is fine. I didn't want more souls to join my choir today anyways."

As for suggestions for his new ult if he were to get one, I have none currently. I just woke up a bit ago and saw this post: http://boards.na.leagueoflegends.com/en/c/gameplay-balance/3tTY3wIR-karthus-will-become-more-usless-thanks-to-edge-of-knight And it was just kind of was like, "Dang man, they're right." I personally love the Death Singer, he will always be one of my favorite champions to play and I just feel like he's been long forgotten to the point where Riot doesn't even consider too much how their new updates will effect him. His play rate is almost nonexistent as well, I see maybe a single Karthus player besides myself like, maybe once every 3 months at most? The rest of his kit is beautiful still but I feel like getting a new ult would do Karthus a world of wonders. Maybe even make him meta again, though that is just wishful thinking on my part.