[Verjigorm]

Simple solution: Don't make them Short. Mindflayers are SM0, so they're tentacles by default are reach C, and adding Short doesn't do anything for you. In the case of Mindflayers, they seem to be all over the place in terms of how long their tentacles are, with earlier editions having shorter tentacles, and the newer art showing longer tentacles. If you give them Long tentacles, they can snatch out to Reach 1. I'm going to assume ST12, or ST 10 with +2 Arm Strength(Tentacles Only, -20%) that gives the tentacles ST 4 or 5.

A Mindflayer who wants to snatch someone by up by the head gets +4 to hit with only it's tentacles, and +8 if it uses it's hands as well. That allows them to easily target the Face/Neck at +1 or +5, or the skull at +0 to +4. This allows for them to easily grab a hold of somebody, and if they use their hands, they can easily use deceptive attacks to penalize their opponent's ability to defend.

The low ST of the tentacles precludes them from using most weapons: you need atleast ST5 to get into the smaller Knife weapons, and your base damage of 1d-5 or 1d-4 thrust and 1d-3 or 4 swing arn't going to go well with the low modifiers for those weapons. The best tactic you have is to snatch someone.