I agree that Cuirrassier rush is irrelevant, since there is no creative leader with a unique unit based on the Cuirrassier. On the other hand, how quickly one can win is very much a primary goal in deciding which creative leader is the best (which can be said to be the sole reason for the existence of this particular thread).
Sun Tzu Wu
I disagree with you on three points here.
1. I measure importance based on securing a win versus time how early a win is. This is obviously an opinion, but it's an important one because HOF players are going to look at things completely different than other people.
2. Cuir rush is not irrelevant. While the Oromo rush is a significant buff to muskets, what is the point of it if they are still not better than cuirs. (You seem to think oromos are still a little better, I think cuirs are a little better (Stronger tech position). Regardless I will at least admit that it's close. But even if they were even, that means oromos aren't adding a real benefit, since you could just go cuirs instead. It's very rare that you cannot secure horses/iron at this point in time. Similarly cataphract rushes can work, but are not necessarily better than cuir rushes, which come soon after. This doesn't make the UU good, it actually makes it near meaningless in a total % game winning sense.
3. Mouseketeers ARE cuir substitutes though. They are not a buff on muskets. By changing the unit to a two-mover it effectively changes what unit it is. Instead of the single mover with option of siege it becomes a two-mover dynamic. Furthermore it's a very significant buff to cuirs, because they are draftable and you can get a head start building them before cuirs sometimes (Depending on tech path). There are also several ways that mouseketeers make cuir rushes more efficient. Most notably.
- Stack defense (b.c of tile defense bonuses)
- Stack defense (in particular against pikes)
- Picking off random pikes the AI has running around.
- Killing weak units for less hammers. This is a very big one. A lot of time cuirs are promoted with the withdrawal promotion, and the first wave of cuirs the point isn't even to kill the units, it's to weaken them for the backup cuirs. Except you don't really need backup cuirs at this point. Mouseketeers are more efficient.
Since musketmen units can be drafted, this means Mousies are using a different production method. This allows the cuir rush to take advantage of both normal production and draft production and makes it extremely strong.
In order for Oromos to be > musketeers you would have to argue that Oromos are significantly stronger than cuir rushes, because musketeers + cuirs are significantly stronger than just cuirs. While cuir rushes might be bland and oromos more fun, I don't think oromos are much better than a normal cuir rush, if at all -- and that is entirely relevant to a debate between oromos and musketeers.