Multiclassing

I really don't like multiclassing. To do it well and make it work is hard, and it is not just "well, my story says I have become a bard for a while, so I guess I will level bard!"

If you start treating classes as jobs and story progression, you will make a mess out of your character.

The character sheet will blow up, get so complicated, spells will double up, and you will end up losing character power and falling behind the others. It is a constant headache; you may love the "get something cool" as you pick different class levels and combine things, but you will fall behind those who do not multiclass if you do not plan (aka, read the cheat guides), and make your picks from a very small viable pool of combinations.

Most multiclass combinations will make you unhappy in the long run.

Multiclassing takes very careful planning to make it work well, and your choice must be extremely limited and focused on gaining only the powers you are trying to get. If you do not plan, you will make your character worse as you level.

Other classes will be dropping 12d6 damage attacks at level 14, and you will be throwing around two or three d10. You won't feel you are "keeping up," and others who stick to one thing will have their high-level features become available, and you will have to wait, and possibly never get them.

You will have great versatility, but you will fall behind compared to others. If you never play past level 12, you will likely never care and welcome the short-term versatility. If you play into the late game, you are either exploiting the rules and OP, or you did not plan and are completely hosed and worthless.

My multiclass character sheets blow up, and I need spreadsheets to track spells.

There are times when I would rather bolt on an external progression system to a character than simulate external path progression. Sure, somebody writes and bolts on a gladiator system for 5E, rather than make a gladiator class. At least, any character could be a gladiator, and the system isn't "messing with my build" by forcing me to take levels in gladiator just to be able to excite the crowd and gain support.

With a bolt-on system, I am a wizard 7 and a gladiator rank 3. Thank you. Keep your silly ideas out of my character build. Later on, I can level up another bolt-on system and become a rank 4 pirate, and not affect my wizard progression or knowledge. Oh, and I can still get my level 20 class feature with these bolt-on systems active. Without bolt-ons, I am a wizard 7/gladiator 3/pirate 4, level 14 total, and unhappy I can't cast spells as a level 14 caster.

Then you have the problem that online character creation systems don't support bolt-on systems. It is a constant headache that a point-buy skill-based system (like GURPS or Champions) just does not have. There are certain campaigns with organic ability and skill progression that I absolutely will not play with 5E since it can't do those sorts of games as easily as GURPS, Champions, Savage Worlds, or a point-buy system.

Yes, I like 5E, but they are forcing a class-and-level system game to do things it was never designed to do. It will start off great, but eventually get worse and worse as the different-shaped pegs are forced through the square hole.

I am happy that Tales of the Valiant, by default, makes mutliclassing optional. I would not play with it at my table or in my games. Most of the time, without careful planning, allowing unlimited multiclassing makes players unhappy and increases complexity to the point where its value is questionable.

Plus, ToV's classes are fun enough without multiclassing, as you get something nearly every level. For the complexity and mostly junk builds that multiclassing adds, I don't see the point.

If Kobold Press delivered a "multiclass strategy guide" with successful combinations that I could automatically green-light and allow, that would be another thing, since the designers thought through these builds and made them more widely known. Players could have a book to consult for winning builds and strategies, so they would not make mistakes they would later regret. A guide like this could make "class synergy rules" to buff weaker combinations and make those viable.

But leaving it up to players (or myself) to stumble through is a pain I don't want to deal with, not in a system where character sheets balloon to dozens of pages at higher levels.

If most of the choices are bad ones, and only 5-10% are viable builds, why do I want this in my game?