First of all, Rock Slide is 100% useless on Slaking, since Return (if you'd have it) does slightly more damage than super effective Rock Slide (and already OHKOs Charizard/Moltres/Articuno) other than to Aerodactyl who then gets hits by Focus Punch for just as much damage as super effective Rock Slide. Use Earthquake over it.
Second of all, Hyper Beam on Slaking sucks, you use Hyper Beam, then opponent switches in Heracross / Medicham / Tyranitar / something else that can OHKO you, and you won't be able to switch. If you'd have Return, then you could switch after you hit something with it, and Hyper Beam doesn't KO anything that Return doesn't other than Weezing iirc, who takes plenty of damage from Return already. Use Return over Hyper Beam. Especially recommending this since Slaking is the main thing on your team who doesn't get walled easily as long as you can predict (or if you can't, then you shouldn't be using it in the first place anyway).
Third of all, you say that you counter most OU threats, including TTar. Saying TTar separately is ironic, since you coincidentally have one of the biggest TTar weaks. Boah destroys this team as it is, T-Bolt probably 2hkos Blastoise, and Kingdra eats a nice Focus Punch on the switch or from behind a TTar Substitute. Physical TTars, such as DDTar, CBTar or Sub TTar all handle your team well enough, Blastoise takes too much damage from them with no Leftovers recovery in sandstorm + no Rest. Plus, TTar gets free switch-ins on Hypno and after Slaking has hit something. Rest on Blastoise won't remedy this much without having Heal Bell on the team.
You also say that you can counter Skarm and Bliss. How? Hypno/Blastoise/Kingdra and even Steelix get walled by Blissey, while Skarm walls Scizor/Steelix and Slaking can only damage it with Focus Punch. Slaking is a very shaky Skarmbliss counter though, especially with no Wish support, it will get taken down easily.
Also, Scizor doesn't counter Heracross. Heracross used switch. Something has to be able to switch into something in order to counter it, but Scizor takes a huge blow from a CB Focus Punch, and is probably 2hko'd by CB Megahorn. That being said, nothing on your team can safely switch into Heracross, while it can get free switch-ins on Steelix / after Slaking killed something / can easily switch in on Blastoise too and can easily survive one Psychic from Hypno.
Zapdos weak too, Steelix can't hit it other than Exploding on it or Toxicing it (since Zapdoses mostly carry Resttalk, the latter option is nullified), Hypno is like 3hko'd by Thunderbolt, and the rest is killed even easier.
Bulky waters aren't covered either, Toxic Milotic outstalls your whole team other than Slaking.
I could go on with listing more weaks, but it would take hours and I've just got bored.
Also, in competitive battling, you have to usually choose between wether you want to win or rather want "coolness" / want to use your favourites. In the case of the latter, what's the point of posting a team, since "fun" / "favourites" teams aren't mainly meant to win anyway, but then what's there to fix on them?
/end of tl;dr wall of text
P.S. Sup Mullet
np: Maurice Ravel - Bolero
Have a nice day.
Edit: Oh, just noticed that you said that you don't have the EQ TM and then realised that this is an in-game team. Most of my points still stand anyway though.
