The underlings of a Marshal are no where near the capabilities of the underlings of a Mercenary Captain. For most of them their only underlings will be Grooms, which while I am friends with many are not a high skilled position. You average Marshal will not have a full time blacksmith or leather worker on staff, since they do not have a high enough demand (or their employer does not have enough income to keep underutilized craftsmen on staff). Baring exceptional figures (the Marshal of England is NOT normal) they do not have any men-at-arms or combat capable underlings.
The Marshal of England should not even come up in discussion of the Virtue, since in 1220 the position was a hereditary position held by knighted noblemen. It was an Earl at the time (where Earl Marshal comes from) before eventually becoming a Duke.
If we created niches for every comparison in titles we are going to need a lot more categories than minor or major. In the unussual case where a marshal is also a titled position they can simply be allowed to have an additional status, but I certainly wouldn't see a marshal, who takes care of cavalry horses being a higher title than a warrior, which is essentially a non-noble soldier, and a minor virtue.
Having done a bit more research, I would like to withdraw my objection to removing martial abilities from the Marshal. I still don't see it as necessary, but I have no objection.
A lot of it doesn't feel like errors so much as preferences. So I was much happier seeing it in another thread. David's attention can certainly be drawn to other threads when needed.
Much of the magical part seems to disregard the Gift or the additional costs associated with it as well as Hermetic Magus. Hermetic Magus gives you 240 experience and 120 spell levels over 15 years instead of your normal 225 experience. Those 120 spell levels are theoretically in the ballpark of 3 seasons of instruction worth about 10 experience apiece, so Hermetic Magus gives on the order of 45 extra experience as well as letting you pick up an additional point of Virtues. If I take Amazon with my Gifted character, is it worth so much more than Hermetic Magus? Meanwhile, for the unGifted, you tend to be required to spend at least 4 points in Virtues and need to match them with appropriate Flaws for Ordeals out of your initial allotment to even be able to take this Free Social Status. So the question for Companions should really be if this 4+ points of required Virtues should really be 5+ points of Virtues, not whether this sole 0-point Virtue should be a 1-point Virtue. That's why the note showed up in the first of these posts about Folk Witch being acceptable for a Companion.
Call them as you wish. But it was David Chart himself who solicited explicitly stuff like "Almogavar should probably be upgraded to a Minor Virtue, given it provides access to a restricted class of Abilities without drawbacks, like several other Minor Virtues". Amazon is exactly the same as Almogavar.
Hmm. Now that coud be a name that finally spells Ars Magica's commercial success! Amazons & Almogavars
Alliteration's Allure!
Latin's for Losers!
Nobilis, Continuum, Universalis, Polaris... fantastic games doomed by their names!
Ok, ok, back to the main point.
If that's the case, your point about that specific Virtue is certainly correct. But as far as I can tell, no, you can create an Amazon grog warrior with no magic whatsoever (check out Polemusa, RM p.20, noting that if you swap out Self-Confident which grogs can't have for another Minor Virtue that grogs can have ... there's a grog warrior Amazon for you).
This is unfortunate, but too complex to change in errata. I think Rival Magic should probably be changed, but it's a whole story seed, not a simple note, and the whole thing would need to be rewritten.
Reopening because I forgot to note: the text in TME does not explicitly say that the rituals are D: Mom, so this is not an error. It might be a little unclear, but that's not what errata are for — at least not in minor features of supplements.