The cooldown was reduced drastically, but the drain damage was not, it's impossible to lane against a pugna, or even kill a pugna with the new 7 second CD, as there's almost no down time between decrep and drain. The biggest issue with the change IMO, aside from pugna already being broken before, is that she has an extra 4000 gold , compared to having to dump money on an aghs with the old longer cooldown.

Here's a list of potential fixes.

Rework Decrepify to instead nullify outgoing and incoming physical damage X amount of times on a target, but still allow them to attack for procs potentially. Keep the increased magic resist, but remove the slow, adding a 1-2 second slow on nether blast instead.

Also increase the mana cost of Decrepify in general, or it's cooldown. Or make it castable only on pugna and her ward initially, making it a level 10-15 talent to cast on anyone.

Cut the damage of drain in half, but give it double healing to pugna, keeping the 7 second CD, also reduce it's range and/or duration maybe, without the perma slow it would be easier to escape.

Give Q a longer CD, that's reduced based on the number of units killed by it, or less damage that scales based on something.

Reduce base movement speed by 10, adding it to the MS talent.

Cut the damage of nether ward down, or make it place a DoT for the damage instead that can be potentially dealt with with a dispel.

That's all I got for now, I feel the hero is completely broken for the majority of the game unless you have some way to blow her up.