Alekseeva was taken down, in some cases multiple times, by lesser grapplers than Dixon on the regional scene. If Dixon is able to get on top she has good top pressure as well as ground and pound. Irina has poor conditioning and will likely tire if Dixon is able to take her down and control her for even part of a round. I have seen Irina begin to noticeably fatigue as early as the sixth minute.
Both Alekseeva and Dixon have been inconsistent on the feet. Neither of them has a meaningful advantage in the striking imo. Irina though I noticed has a problem taking calf kicks, doesn't check them, and has compromised movement as early as the third calf kick absorbed. Dixon throws hard calf kicks.
A lot of folks have only have seen Dixon's last fight where she faced a very good striker, who was later signed by the UFC, and think she doesn't have any striking because of it; her hands looked pretty fast and powerful in this fight:
Dixon is the rightful favorite imo, I cap her at 60%, which is roughly where her betting line is currently at.