Ok here are some criticisms but sent by an admirer of your work so don't get all RPLASS RAGE please!

I think the picture lost the concept of foreground/background. The figures in front fail as foreground figures for facing away from the reader, and the background figure, Storm, fails for being too small. The central element is the Sentinel, but he's so far away and has no sense of threat to him.

To improve, make the Sentinel scarier, attacking, moving, threatening, with hands up about to blast. Storm much bigger. Guardian and Cyclops a lot closer to the Sentinel and facing the reader. Make the foreground the characters and the background the Toronto skyline. If you're going to use a city skyline as a background, that's great but put in more buildings and more city. Finally, that mixed case text in Cyclops' speech bubble - change that to a hand drawn allcaps font or download a comic font and reprint it in all caps and with some ooomphasis. Refer to UXM #109 how JB put a speech bubble on the front cover of a comic and use that technique. Oh and add in more Alpha Flight members.