My Audio Technica AD700X broke, so instead of just replacing them I thought why not get something better (hard to imagine though they were that good!) I did love them, mainly how comfy they were, normally headphones and me just dont mix, I cant stand pressure on the sides of my head but the AD700X were fine.
It is mainly for gaming (positional sound and accuracy), and I did like how there wasn't much bass on them, things sounded realistic and not as though it was coming through a sub.
Avoid any gaming headset, headphones are the way to go for quality. The Beyer's are a good choice, given similar pricing (at least in the US) the DT 990 Pros would be the better choice. They are much different from the AD 700x, the lows and highs are emphasized while the midrange is recessed. For gaming this can be helpful as gunshots and footsteps will be easier to pick up.
I had a pair of DT 770 Pro 80 ohm version, great headphones. Solidly built (made in Germany) though light weight and comfortable.
The one issue you may come across is amping, with the DT 990 Pro you would need an external amplifier to properly power them. Onboard likely won't sound as good as a decent amp and you might also find them lacking in volume. For $99 the Schiit Magni 2 would work great.
If you are looking to replace the AD700x with a similar sounding pair consider Sennheiser's HD 558. No amp would be needed either.
you say that you like how the ad700x were bass light? the dt770 is the opposite, it is bass heavy. this will cover up things like footsteps more.
the dt990 is also bassy but not as much as the 770. you can certainly find enjoyment in these if you dont mind having more bass output. the 880 is more neutral so if you want mids.. those are the ones to go for.
generally good treb/mid presence is ideal for gaming since gunshots fall into both treble and mid categories depending on effect. if you only have treble and reduced mids you might miss some while heavier bass might overpower the treble and certainly the mids. i'm not saying its a major issue (and eq can change this a bit) but its just worth noting.
the ad500x/ad700x have more soundstage / 3d sound. you wont find better in that price bracket.
the akg cans like the q701/k701/k702/k7xx will have similar sound signature to the ad700x but are harder to drive and picky about equipment so you would need decent dac/amp setup for those.
the hd558 will be more neutral than the 700x... with a bit more bass response and a bit less treble response while being a whole lot more mellow same with the hd598.