You're not the first to ask...
Sage Advice Archive said:
Q: Dear Sage,
Could a crusader (Tome of Battle, p.8) choose to learn or ready fewer maneuvers than he or she would be entitled to?
--Joe & Sam
A: No.
You must learn and ready the full number of maneuvers entitled to you by your level.
Otherwise, you’d be able to cycle through your favorites faster, which defeats the purpose of the crusader’s unique recharge mechanic.
Of course, the Sage's rulings are only worthwhile if you believe that he's right more often than not. Hands up, anyone?
For recap purposes, here are the relevant rules (emphasis mine):
Crusader said:
You can ready all five maneuvers you know at 1st
level, but as you advance in level and learn more maneuvers, you must
choose which maneuvers to ready.
You ready maneuvers by praying for 5 minutes. The maneuvers you
choose remain readied until you decide to pray again and change them. You need not sleep or rest for any long period of time in order to ready your maneuvers; any time you spend 5 minutes in prayer, you can change your readied maneuvers.
The way I see it, you could read that either way. You could argue that it's your choice which maneuvers to ready, and that such a choice naturally includes
how many maneuvers to ready. You could argue that the phrase "
can ready all five maneuvers" is not the same as "
must ready all five maneuvers" and that as such you can ready fewer.
Alternatively, it could reasonably be argued that the apparently-optional bit at the beginning is just there to clarify the fact that at later levels you can't ready all the maneuvers you know and will thus have to choose a sub-set. As such, you'd be reading that first sentence, more or less, as "You can ready all five maneuvers you know at 1st level: this doesn't mean you have the option to ready fewer, we're just making the point that you won't be able to ready all the maneuvers you know later on."
The class text at no point contains anything that definitively establishes how it works one way or another.
Much as I hate to bring this into it, this is one class where the DM's fiat is quite reasonably the final word. You pray for maneuvers. They're granted or withheld by a divine being of some sort or another, round by round, on an arbitrary basis. Annoy that divine being by trying to get slippery with the way your maneuvers are granted, and you may well find yourself not granted any at all...
Conversely, your deity might be bang alongside the idea of letting you get away with it. A deity that admires cunning - or simply one that wants his Divine Crusaders to stab as much face as possible - could well be delighted at your little exploit and thus keep handing out the asswhuptastic goodies without let or hindrance. If they're sufficiently chaotic - or your DM sufficiently undecided - it could be a coin-toss between you being granted "maneuvers" or "a lightning bolt to the pre-frontal lobe".
As you're going into Ruby Knight I-Windicator, I assume that your deity will be Wee Jas unless the class has been house-reflavoured. I have no idea whether the goddess of death and magic in your campaign would be up for a little light class-feature chicanery... On this occasion, the rules text just doesn't support one position over another to an extent adequate to override the "god decides" fluff. Rule Zero is of course always in force, but sometimes it's more obviously in force than others, and this is one of 'em. Sorry
EDIT:
1) It's worth noting that the Divine Recovery ability (Windicator 2) not only allows you to recover a maneuver as a swift action, but that the maneuver is also
immediately granted. As such, you pretty much can recycle the same couple of maneuvers over and over, at least until you're forced to take an immediate action. I realise you still have to wait for the ones you want, if your DM didn't allow you to ready fewer, but it's better than nothing.
2) Again, sorry, but there's nothing in the rules to suggest that prestige classes which advance your initiator level also allow you to swap maneuvers. The swapping is based on
class level, not initiator level: the way it's written, it's essentially a class feature. As such, unless a prestige class says otherwise you can't use levels in a PrC to swap out lower-level maneuvers. The Sage said:
Sage Advice said:
Q: Can you switch maneuvers that you know for ones that you don't know?
A: Yes. The crusader, swordsage, and warblade can trade one maneuver known for another at certain levels (see their respective descriptions in the Tome of Battle). (Prestige classes that grant maneuvers can't trade maneuvers known.) However, you may only trade one maneuver known for another at a time.
Just for once, I agree.