Maybe your stat gains will get better with the next couple of levels. It's still pretty early in the game, and I've had some rounds of bad stats.

What are you planning to make the other villagers into?

Mine wasn't too far off.

Gray - Mercenary
Tobin - Archer
Kliff - Cavalier
Creepy Unrequited Crush Girl - Mage
Atlas - Cavalier

Can't remember my thought process for most of them...guessing it was just that I wanted certain units to fill out my team. I think Tobin had high skill when I promoted him, so I decided to put him in a class that requires it. Faye because magic users seem rare in Alm's side, and Cliff because he had high defense/resistance and served as a good tank.

Also...I finally maxed out a unit. Got Clair to level 20 after a few hours of grinding in the Sylvan Shrine. 

My plan now is to promote villagers at ~10-12 (assuming there's any others), most other units at level 15, mages at ~18, since many get new magic at that level, and Clair at level 20.  I need to keep seeing that physical perfection.

Not sure yet. Kliff is largely useless for me, so I may make him into a ranged class. Gray is likely to be a cavalier and Tobin make jump to Mercenary.

That may be a good idea. I did that with Kliff and it worked out pretty well in the end. Giving Gray and Tobin those classes sounds interesting. Most people make Gray a mercenary. I'll be curious how that plays out if you go with those choices.

The grind can be mitigated by abandoning the common class change logic. Forget about getting to level 20 in most instances.

Any male character that starts as villager, mercenary or myrmidon can enter a class loop: Villager > mercenary > myrmidon > dread fighter > villager. Level up to 10 in each class (that's the point where EXP gains drop off and they scale differently for new classes in this game, so going back down to level 1 is definitely preferable), then promote. Once you are back to villager, you will have pretty good stats and can pick something other than the mercenary path the second time. Stats cap at ~40, except for HP which is notably higher. I doubt that a second class loop will grant notable benefits.

Cavaliers, archers and soldiers each have two additional classes, so promotions at level 10-15 are sensible. Only the male mage is limited to one higher class, so going for level 20 before promotion should be considered.

The female-exclusive classes cleric and pegasus also have only one higher class, so level 20 is up for consideration; for clerics it's not really an issue because healing EXP remains okay all the way. Female cavaliers and female mages follow the same logic as their male counterparts.

Every character, excluding Alm and Celica, can return to villager with the item Villager's Fork. The game's free DLC provides two of these one-time use items. One is already available for download, the other will follow in the near future. Players can pick their most favorite characters and send them through a loop. The only stats that class change adjusts are those which are below the base of any given class; everything that is the same or higher is unaffected.

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In other news, the turnwheel cannot change the stat gains for a level up. This RNG is determined upon the start of a battle, so the only way to alter it is to load a save file from before the start of a battle. This is in line with Fire Emblem Fates where it works the same and repeated quick saves on non-classic settings cannot be abused to grow stronger characters. This cheap exploit works in Awakening (on non-classic) and Radiant Dawn (on easy and normal difficulty), but in RD's case it's essentially redundant because the average stat growths allow players to max a bunch of stats without cheating anyway.