Rhodok is the way forwards, prepare to be enlightened in the way of peasant warefare!
firstly, they suck individually- remember that, but they are like cranium rats in that they grow stronger in a collective horde, even their cheap low-teir spearmen (not raw recruits) can make for great meat-sheild mobbers when tightly packed, rhodoks aren't a matter of grabbing as many top-teir troops as possible like other factions.
personally I have a core of tier 2-3 spearmen as my bulk human shield, littered with stronger troops in their midst to deal the damage, with a horde of crossbowman behind them (whilst sharpshooters are badass, it can pay off to go for the cheap option and simply try to get as many bolts in the air as possible, depends if you want precision or cluster**** damage).
Tactics are very important, and vary depending on your opponent- you can tell your crossbowmen to hold fire, so they will bring out shields- for times when under heavy archer fire, and likewise, you should probably use "advance 10 paces" multiple times for your infantry rather than issuing a "charge" order, so that they keep shields up and keep in something resembling a formation.
The new feature of being able to separate up your troop types into squads is fantastic for Rhodies, you can have 2 crossbow squads- your marksmen and your 'cluster**** showerers' who you can use to attack from different angles to bypass shields.
you can put your new pikemen a few paces behind your frontlines, so that they can give assisting jabs to your regular infantrymen too, rather than being bogged into battle.
you want your CHA and leadership pretty high, so you can accommodate their large numbers, but remember that they shouldn't be costing you too much.