@PryorConvictions: Well, without SR some Pokémon will be moved to the Ubers, and some others from UU/RU to OU pretty easy, so, the "broken" status is not really a problem removing SR. And yeah, actually, SR make them more powerful because almost all their counters are weak to SR (for example: Dragonair hate STAB Ice Beam, but all the stab Ice Beamers are weak to SR, and because they are OHKO'ed after a SR, their are not used at all).
Also, some great stallers suffer A LOT with SR, and thus, are barely used because that, so, and really, seriously, a metagame with SR could be completly different, but not "more offensive" or "defensive" than now, and a good proof is how it was on Gen 1-2-3 (specially 3, pretty more balanced on defensive and ofensive).
Anyway, the status moves are not broken (even Sleep without Sleep Clause, becase Pokémon bring you a lot, but a lot of sleep counters in that circunstance), they are great for the not offensive Pokémon and make the game more balanced, and the all other entry hazards (except SR) are pretty balanced on general (and help again, with the variety).
Stealth Rock by other hand is extremly overpowered, for the mere reason that move make unnable almost the 80-90% of the Pokémon to competitive levels, and the who can get benefit of it, a good number of them are on OU only because they resistance to SR (or for being spinners or blockspinners), at the end, the metagame of 4 and 5 generation is total oriented to SR (a Pokémon is bad or good? Look at him if he can OHKO or 2HKO with SR or survive with SR, if he can whatever of both, he's good, otherwise is ugly, or just read the recomendation of each Pokémon of OU/UU and you'll not be able to avoid the words Stealth Rock at all).
Anyway, Toxic Spikes is not a useless move, it can be pretty good, and Toxic help some Pokémon to make stall an able option.
I love Caterpie, he's a so adorable little bug! ♥ (Also, sorry for my English, I'm still learning it and I'm not a native speaker).