For the record, the dinos with 50 or 75% decel resistance but no slowing moves are:
Monolorhino, Allosaurus G2, Antarctovenator, Dilophoboa, Edaphocevia, Erlidominus, Grylenken, Paramoloch, and Spinoconstrictor.
Dilophoboa and Erlidominus have moves that increase their own speed, so they can get their speed up to the point where their resistance starts to matter, especially with boosts. So even 50% resistance can help them. Their speed increases get removed by resilient attacks though, so it isn’t helpful as often as it could be.
The rest all have no speed control moves at all. It doesn’t mean that their resistance is entirely useless (like in raids or when heavily boosted), but that doesn’t mean it can’t be made more useful.
Monolorhino is the only one of these with 75% resistance, but it’s natural speed is still only 101 after being slowed, which isn’t great. It can benefit from boosts fairly easily though, so it probably doesn’t need to change.
Allosaurus G2 is too slow to benefit from this resistance outside of raids without heavy speed boosting, even if it had full immunity. They could probably give it full decel immunity, leave it as is, or remove it entirely, and it probably wouldn’t affect pvp very much in any case (expect for nitro boosters with full immunity). So it really depends more on what’s best for raids.
Antarctovenator could be given some kind of slowing move, maybe decelerating counter, but that may be too strong. It may be fine just having 50% decel resistance for raids, or maybe even full decel immunity. It’s slow enough that nothing else benefits it outside of raids, and I think it has enough other weaknesses in its kit to balance it out.
Edaphocevia could also be given full immunity from it’s Edaphosaurus ancestry. It could also be given 75% decel resistance, putting it’s speed at a respectable 111 after being slowed, so it would still outspeed some stuff.
Grylenken currently lacks a speed control move, but giving it Sidestep instead of Evasive Stance could be one way to give it such a move. It’s plenty fast enough to get some use out of 50% deceleration resistance after increasing it’s speed.
Paramoloch is a raid dino, so it benefits from it’s resistance in raids more often than perhaps most of these dinos do. However, I don’t think it gaining full immunity to deceleration like Tuoramoloch would make it broken either.
Spinoconstrictor is an interesting case. Besides it’s wounding counter, it’s entirely cunning, so deceleration should counter it. However, at the same time, I can’t help but feel like having decel immunity wouldn’t break Spinoconstrictor. Feel free to correct me if I’m wrong there. It could also benefit from switching Evasive Stance to sidestep like Grylenken, though it’s lower base speed might mean it would require more speed boosts to really benefit from the 50% resistance.