Evaluate is basically unused in my games.
The benefit is a bit small (+1 per turn, max +3, one turn per plus), ends early, and generally is superseded by other, more useful options. Low skill? Turn to Telegraphic Attack, Committed Attack, or even All-Out Attack. High skill? +1 to +3 just isn't worth it. Even skill with your foe? Probably better to bet on a critical or a Feint* than to Evaluate.
I've written about ways to upgrade Evaluate before, but since I never seen these used in play I didn't keep track of where I wrote them. So I gave it some thought this week once Doug assigned it out as homework.
I see a complex way and a simple way to upgun Evaluate.
Evaluate is a Per-based Feint. It's useable against any foe you can see, subject to range penalties. The foe resists with either DX-based or IQ-based skill, to conceal (or fail to create) any openings. You can hold your Evaluate bonus as long as you continue to Evaluate your foe. In addition, you get the usual benefits of Evaluate (+1 to +3). You may choose to keep the results of your Per-based Feint or you can try again and take the new results. The bonuses for the Feint and the Evaluation do not stack; take the higher bonus.
Evaluate works as written in Basic Set and Martial Arts, but the bonus is +3 for one turn. Additional turns of Evaluate do nothing exceed hold the results.
(Optionally, make it +2 per turn for up to 3 turns, for a possible +6! In that case, only apply half the bonus vs. Feints and Deceptive Attacks. Cancelling -3 is good enough for those.)
I'd go with the simple way. Just hand out a +3 and it's suddenly worth it for many fighters, especially since it can stack with All-Out Attack (Determined) for a +7 to hit without giving a defense bonus to the target ala Telegraphic Attack (Martial Arts, p. 1113). At the same time, it's not quite as good (but much less limited) than Telegraphic Attack. It's better for slightly more defensive minded folks - and cancelling 3 points of Deceptive Attack means you can hold your own, potentially, against a fighter 6 points more skillful than yourself!
In any case, it's important to apply all of the benefits of Evaluate fully - the cancelling of defensive penalties (per Martial Arts, p. 100), bonuses to non-combat skills, and so on. If you don't do that, even the changed versions won't help much.
* Yes, I know that mathematically Feinting a person of the same skill works out to a net zero. But Rock Paper Scissors works out to a net even win-loss over the long run, but it doesn't mean people don't win on some turns. Feint vs. a similar skill foe is betting an attack chance that you'll roll better than your opponent this turn and then mess him up on the next turn. That's, in my experience, a very good choice.