Yes and no. Ppl have been gaming on 50" or bigger 1080p Tv's for years. The difference is distance between the head of the gamer and the TV.
On a standard desk, with a monitor stuck near the back, the gamers head is approx. 3½ feet away. At this distance, a 24" 1080p smaller pixels blend the way a 50" 1080p TV does at 10ft away. At 27/28", the pixels at 1080p are physically larger, so if your head is the same 3½ft away, it's going to look grainy. Like sitting up close to the big screen Tv's.
So a 27" 1080p is just fine for gaming, as long as you get your head further back, not at the same distance as a 24".
Most ppl who will not change distance, will move to 1440p at 27" as the pixel size is slightly smaller and @1.7x more dense than a 24" 1080p, so making the picture sharper and clearer.