and we already know that casual player wont win those prizes. Top 16 player will be who play coh2 in their whole life. and if you want when the brackets will out i will bet you their names( and i will hit the 90 % of them )
To make the most of a 120/144 Hz monitor you need a good computer. Otherwise you wont notice the differance in game. Since CoH isn't that well optimized maybe a IPS panel is preferred.
With a 60Hz monitor you can only see 60fps but with a 120Hz monitor you can se up too 120fps.
IPS panel or 120/144 HZ TN panel is the question you should be asking yourself. I recently bought myself a 16:10 IPS panel myself and I love it so far. The colors are godlike compared to a TN panel.
And if you would upgrade to a 1440p screen I guess you would need to upgrade your GPU. Depends on what you play really.