Paladin doesn't really need all the levels, can easily multi at, for example lvl 14.
You won't lose much.
Depends if you have the Divine Mount or Divine Weapon? A pet class need its level to be effective altho granted you can multi into something with Pet (e.g. Cav).
For the most part full Paladin works good enough for the base game altho with Boon Companion you can take 4 level of other Class multi with Paladin + Divine Mount. Bard/Sklad 4 Paladin 16 can be OK I guess? Archmage Armour iirc is always good later and running naked + Archmage armor + plethora of Dex buffs usually ended with higher AC than using Plate Armour+5 unless you are a Fighter
It's just bad. Trust me, I've done both. Pal needs the levels for like ten different reasons. The fourth level spells high among them (some of the best/most unique in the game) and getting the duration up on the ones before that. The 17th level ability is great as well and you want it ASAP.
A shame, as I need my Dirge of Doom ASAP. Normally on Seelah, but maybe I need to look whom else I could multiclass to bard (not Skald, as Inspire Rage cancels spellcasting and spell-like ability use - such as Travel Domain Dimension Hop).
Not Cam/Ember, as they need 8 class levels ASAP for Evil Eye upgrades.
Not Woljif, I love him too much as Rogue/Vivi. Hell, I tend to even mix Freebooter there.
Reg comes with 5 levels taken, so too late.
Nenio? I need my Brown Fur Transmuter.
Lann? Hmmm, maybe? Kinda low Cha for a Bard, though. Thought about making him a Judge maybe.
Daeran? Maybe? But he comes with 3 levels taken, so not optimal.
...perhaps a merc? I don't like them too much, but maybe need to make concessions for a Bard.. and maybe Brown Fur Transmuter, since full companion respecs are screwy.