Instant governors - decent fortress to provide a few free level-ups, plus the trait that grants a free level, and you can pop out a few of these with Commander and a couple levels of the administrative traits fairly quickly. Also works for the Field Commander side of things, though it takes a little while to get to the really good bonuses.

If you have access to the Decalon spellbooks (Pariden or a custom faction with the Decalon is nearby and not at war with you, or you have a custom Empire with that trait), they can also make for decent damage mages. Air I or Water I are all you need for a decent support caster, and these you can get just from reading the spellbooks; Fire II/III is the shortest path to good damage spells but means you'll need to gain an extra level or two after reading the spellbook, and the same goes for Water IV. If you don't have access to the spellbooks, though, I wouldn't bother making these into mages unless you like summoners or want Horrific Wail casters.

I personally would not go for any of the direct combat classes on a single-figure unit.

Technically, per-figure a Sion can be the best Fallen warrior - they can get all the bonuses a fortress or enchanted city can give and they can get the same traits as direct combat champions (which ultimately means that Sions and Henchmen make superior direct combat champions than champions do), and they can start with the best equipment you can produce, which you can subsequently replace with the best equipment you can find. The problem with using them as a direct combat unit is that by the time you can get them, you could have (and be facing) four or five figure units with mid-game weapons and armor. A single-figure unit does not compare well to that at all, since the same equipment means that the units will be dealing on average the same per-figure damage to one another, and if they're both coming out of a decent fortress (or both are not coming out of a decent fortress) they have enough accuracy that neither really has any hitting advantage (although the Sion wouldn't really have much of one anyways, since hits are computed per figure, so a three man unit with a 70% hit chance has three 70% chances to hit rather than one 70% chance to hit for lots of damage - I'm not great at computing probabilities, but I do know that three 70% chances to hit for damage means a much better than 70% chance to hit for any damage, and when you've got the same equipment on a low-level Sion or Champion, that means that the regular unit is probably at least as good as the Sion or Champion).

There is/was also a Scions mod for download....saw it another thread. I'm just about to explore the possibilities in a game I'm playing.

I never tried sion, but it seems it's just a slightly weaker version of altar's henchmen. CMIIW

Henchmen spells are incomplete version of the real spellbook path. That being said, hencmen can be build as an excellent mage without decalon books because there are some very useful spells on the henchmen minor spellbook path, like growth/shrink, storm, haste, slow, etc plus the path of the mage.

Because of path of the mage, henchmen is much much better mage compared to original FE's henchmen mage, because there are many good traits in path of the mage, the summoning line make the game very easy at harder difficulty. I assume scion can access this, if yes then mage scion is as good as henchmen, well..., maybe a slightly lesser version of it. The only different is the incomplete spells which henchmen has (though some are excellent spells)

Yes, not only heal but it can also have growth/shrink, which is the best spell from adept books (henchmen spellbook).

I guess why Sion is slightly weaker than henchmen is because it is available to all fallen factions, while henchmen is only for altar, other kingdom faction doesn't have it.

Wait, Sion can't be a governor?

Yeah that's a good idea, and show the traits info on all class too.