This game is aiming at balance, by bringing everyone up to top tier status.
You can't cancel Side B into grab. Dash Grab was made to look like side B.
Endlag isn't the weakness of the move. It's the frame disadvantage on block. It's very large and if people stop acting scared of Wario, they'll be able to block Side B more consistantly, forcing wario to rely on it less.
And even then, the move's power only grows as it travels, but the longer the distance you have to travel, the more time you're giving your opponent to react. It is strongest off stage where the opponent has very little options, but even then if you miss, that puts you in a worse position than your opponent. At least a lot of the times it does.
And you can only DJ out of it after jumping with the side b first, iirc. And even then, the ability to DJ out of side b is relatively late and it only works from the ground. Aerial side b goes into free fall and you can't DJ, iirc.