Basically need a laser version of the proverbial optical RTS mouse. Two buttons and a wheel is enough. Preferably no side buttons. No — or ability deactivate — prediction, accelaration and other monkey business, so you can opt for 1:1 and rely on muscle memory. Preferably scalable dpi to not be confined to either a low-sens or hi-sense style, just in case. Light-weight construction and wide, whatever the form-factor is. Speaking of form factor — better an honest claw/palm/fingertip-gripper than a hybrid. If a palm gripper, then made for people with large hands.
Wired unless being wireless 1) won't make it die on you during a game (advance warning at least 1 hour and hard to miss and/or ability to plug a USB cable in anyway); 2) the level of battery power won't in any way alter mouse behaviour (especially sensitivity).