I would not want Odyssey to lose base speed unless it got strong enough to slug it out with any other capital in a slugging match. Odyssey is the only capital warship that cannot do that. (Even Conquest and maybe Legion can stomp Odyssey into the ground without much of a sweat, let alone a enemy battleship.) Some might think its high speed (for its size) can let it act as hunter-killer and bully smaller ships, but that is not really possible with short-ranged weapons due to how the AI fights. You chase down one, and several more surround and attack Odyssey, and 80-something speed is still slower than smaller ships' speed, meaning Odyssey cannot escape quickly enough if things go south fast.
Maybe Plasma Burn will let Odyssey catch and kill small things before its friends have the time to surround and attack Odyssey.
Plasma Jets could be nice, but it would probably make it too untouchable, which is bad if lance sniping remains viable or if Odyssey gets stronger and tougher. Say... if Odyssey has a permanent +50% damage or so hullmod, then lance sniping will probably remain viable, and Odyssey dancing in-and-out easily while picking off ships one at a time would be cheesy, as in encouraged too much.
Currently, lance sniping while constantly kiting or backpedaling is the way to go with Odyssey.