Yeah with the popularity of drizzle teams, especially rain stall teams which Tentacruel faces against, rain dish can not be ignored on a stall team. I used liquid ooze for the longest time and it literally saved me once, in the super extra late game.
But I have not come to simply bump on that, oh no. I am here to persuade my fellow sand stallers to use rest on Tentacruel. I like to bring up the point that tehy made:
Outside of Jellicent of course, this is no longer a problem with rest. Look at Tentacruel's movepool, scald / rapid spin / toxic spikes / ice beam, it is filler, complete and utter filler. I often found Tentacruel dieing to stacked up damage + entry hazards or status, it often rarely set up or spun. Wish rarely helped to alleviate this either. One day I was just like "fuck this shit" and tossed rest on Tentacruel, never looked back. With a little cleric support, (which with Blissey is on every sand stall team) Tentacruel can stay around forever, and it needs not worry about burns because it can just sleep it away. I do realize that this means the opponent must let me do this, but against stall teams, it is going to happen, and against offensive teams, my last worry is Tentacruel slowly dieing to entry hazards. The point of a surprise ice beam on dragon types is mute, considering it’s a stall team, you should be able to deal with Dragonite, and I also have scald which burns them.
I’m also doubting the effectiveness of the current standard physically bulky spread, sure it's great against infernape, but I often wished I had more special bulk when facing heatran which is much more common. I’m currently running calm - 252 HP / 168 Def / 76 SDef / 12 Spd to take earth powers easily, which is good, but I am thinking about dumping it all into special defense, to deal with more offensive ones that run stealth rocks for some reason.