Actually, while they would be cumbersome in clearing doors or corners, the rest of the time a spear is mighty convenient indoors: there’s less space a foe can approach you from, so the spear’s advantages are maximized, and the situation does not hamper your stabbing movements at all, unlike, say, a sword, which would need swinging it around.
@Stone, there are several problems with your logic.
Spears were used, a lot. Granted, this was mostly when they had coordinated infantry, because spears are not only a world easier to use in those tightly-packed situations than just about anything else, they negate most of the weapons’ disadvantages and leverage their advantage against both infantry and cavalry. Yes, they would also carry backup weapons, but they were that, backup.
Even on a more personal scale tho, spears were pretty damn popular for hunting, trying to get a boar or a bear with a sword or knife is just getting yourself killed. A zombie, much like a boar, is stupid, animalistic, and possibly stronger than you, so it’s definitely a good weapon to use.
The other issue is the ‘it’s makeshift and not profesional, so it will suck’. The problem with this logic is that regardless if it applies to all spears or only low crafting spears, it should then apply to all things or only low crafting things as well. If you can’t reliably make a pointy-thing-on-a-stick, you can’t possibly be doing long-sharp-thing reliably either. If all your options for that crafting level are fragile and faulty, you’re back at square one.
I think that, for the purposes of making other weapons popular, what we need is to make it less useful against multiple foes: let zombies get stuck on spears, let zombies grab you or the spear and prevent you from swinging it to the other rooting corpse, etc.
If that’s done, it’s fine if the spear dominates the 1v1 low skill solo hunter kitting scenario, the players would need to switch to something shorter once the zombies get close.
The players would also have the alternative of using a ranged weapon instead of a spear for that kitting job, and since the spear is bigger, other weapons would make better backup weapons since they’d be 'w’ielded faster.