SkunkyArt | PlasmoidThunder

Way too small; coupled with its mobility, it's obnoxiously difficult to hit.

Its hurtbox doesn't extend to the ground, so it can avoid some crouching attacks and lows by default.

It has increased Attack for no good reason, though its attacks are still incredibly weak despite this.

It has increased Defence for no good reason.

Its moveset is horribly uninspired, with its Specials almost entirely being forward-firing projectiles of similar utility and its Hypers all basically serving the exact same purpose depending on the level (level 1s are area-of-effect, level 2s are long-ranged projectile volleys/beams), resulting in a ton of redundancy.

Relatively speaking, almost all of its attacks have really high priority for no good reason.

Most of its attacks come across as spammy and safe, though the biggest offender is Crouching Heavy because it's active starting from frame 4 and +8 on block with no guardpush, so it's a blockstring infinite; conversely, the rare few attacks that are unsafe are really unsafe.

Its combo logic makes absolutely no sense:

You can cancel any standing Normal into a standing Normal of higher strength, but for crouching Normals, only Crouching Light can do this; Rotom cannot chain its air Normals whatsoever.
The only Special that can be cancelled into is Electro Ball.
Although all level 1s can be cancelled into from every ground Normal (excluding Standing Heavy), only Crouching Heavy can combo into them because of how much startup they have.

Standing Heavy, Electro Ball and Hydro Pump are the only attacks that do chip damage.

All of Rotom's air Normals (barring Air Heavy) are active until the character lands, making jump-ins effortless, though it conversely leaves Rotom wide open to being counterhit, should the opponent have such a system.

The secondary taunt is a stupid unblockable move that hits the entire area in front of Rotom and has many active frames; although it does no damage, you can time it while the opponent is lying down so that it hits them once their getup invulnerability wears off, so in other words, it's an unblockable okizeme.

The attack Rotom has in place of a dash/hop is active the moment it is performed, making it unblockable at point-blank range against most characters.

Will-O-Wisp is way too good at what it does and lasts for far too long; some characters can't even jump over all four wisps.

Electro Ball cannot be beaten by other projectiles and it does more damage at close-range because it accelerates; it also lacks a hit cap, so wider characters take more damage than thinner ones.

Charge Beam is a screen-wide beam that comes out way too quickly and makes approach stupidly easy since it doesn't halt Rotom's momentum.

Jump Shadow Ball has similar issues to Charge Beam in that it trivialises approach due to maintained air momentum, but is also hard to avoid.

Overheat is completely useless because of how much startup it has and how short its range is in comparison to Rotom's other level 1s.

Hurricane is unblockable and can potentially do more damage than Rotom's other two level 1s.

Leaf Storm tracks the opponent for the duration of the move regardless of where they are, meaning it will cross the opponent up if they jump over Rotom during startup.