I find the 50% speed decrease resistance to be… unusual. It means speed decreases only slow by 25%, which sounds fine on paper. I feel like the intention here was to have these dinos be faster than at least some tanks after being slowed down, but it currently doesn’t often work out that way - most of the time, this resistance doesn’t seem to matter. The main issue revolves around the fact that the amount of deceleration doesn’t really matter as long as the target of the deceleration ends up slower than the other dino. So oftentimes this speed decrease resistance ends up not making any difference. But even for the fastest base speed in the game (132), a 25% speed decrease puts their speed at 99, which is still slower than every base speed in the game. And if the slowing dino can stack deceleration (like Tryko can over the course of a single turn with it’s counter), your speed will drop even further, and this resistance means even less. With boosts your speed goes up of course, but the slowing dinos can just increase their own speed in response. And boosts don’t count in a lot of tournaments.
So why have a resistance that’s essentially the same as having no resistance at all? I think I figured it out.
These are the dinos with 50% speed decrease resistance:
Most of these have at least one of these two properties:
A. They have a speed increasing move, so that they can still outspeed some slow dinos even when decelerated, as long as they have used one of these moves.
B. They have their own decelerating moves, so when in battle with another slowing dino with a lower deceleration resistance (in this case, none), they will end up faster in the end.
Honestly, both of these are fairly good applications of this 50% resistance, allowing a speed advantage in particular cases where having no resistance would have been worse. It is also more useful in raids than arena, because then you can be assisted by your teammates own slowing moves. However, there are some exceptions that belong to neither category, being Edaphocevia, Gylenken, Paramoloch, and Spinoconstrictor. For these dinos, their low speed resistance and lack of their own speed control options means that in almost every case their speed decrease resistance makes no difference, unless they were given substantial speed boosts. You need speed 135 to beat even the slowest dino in the game (speed 101) while having 50% resistance, let alone the higher base speeds of most tanks around 104-116, requiring speeds of 139-155 in order to stay faster than them after being slowed. Using base speed 108 as a good tank benchmark to beat, the previous four dinos require 9, 10, 10, and 12 speed boosts respectively in order to stay faster. And then you have to consider the fact that the slowing dino can have their speed increased with boosts to counter your own boosting, requiring you to spend even more boosts.
My suggestion would be to set these deceleration resistances to 75% at a minimum for these dinosaurs in order for the resistance to actually mean something, at least for the four listed above that lack their own speed control options. Either that, or give them speed control options of their own, liking giving sidestep to Gylenken and Spinoconstrictor. Paramoloch is mostly a raid creature now anyway, so its probably fine. I don’t think there’s any other options for Edaphocevia though. They just need a higher resistance. Otherwise, their deceleration resistance might as well be 0%.