good OP. as a stall player this opinion is probably gonna sound a bit weird coming from me, but i think the utility of spinblocking is very limited in the modern metagame. even on a full stall team, i find it is, out of all the classic utility roles in stall, the most easily sacrificed.
so hard to find a good spinblocker these days. offense teams and pretty much anything that involves deo-D spikestacking should automatically turn to gengar - this is a tried and true combination and here there's really no contest. gengar maintains offensive pressure that those teams love, and no other ghost has the power and speed to keep up the action in that way. you don't even need spinblocking on these teams anymore (not necessarily, anyway) because it's not too hard to pressure most spinners out by sheer power. if you can crack rain tentacruel (PSYCHO BOOST DEO-D WOO) you can crack them all.
(interesting aside: if you look at lower tiers, where spinners get progressively shittier and spikers remain viable, spikestacking offense becomes stronger and stronger the further down you go. you don't even necessarily need a spinblocker on those teams. look at zebraiken's RMT for The Heist as an example)
stall however is a bit more torn. things like dusclops and cofagrigus look good in theory with their superb defenses. in addition, seeing as they're ghosts, they can spread ever-useful burns. cofag even has haze (prevents setup). the problem with both of them is that pain split is pretty shitty for a prolonged game. chestorest is not great on stall seeing as it's a one time thing. in addition, chestorest is bad when you're playing sand stall, because no lefties means you're taking sand damage.i have been considering it on a few mons though, in one of my next teams. yet pain split is just so unreliable - it's incredibly weak against mons with middling to uninvested health; you generally need to target an opposing stallmon with it for maximum gain. the only option that's "reliable" is restalk, and you don't want to be running restalk, EVER, in bw2 lol.
that puts stall in a bit of an awkward position with regards to spinblocking, which is ironic because it's the style of play that benefits from, and arguably needs it the most.
there are only two spinblockers i would consider using on any defensive/bulky team these days: jellicent and sableye. this is because both of them have recover, which means they aren't absolutely screwed by switching through hazards repeatedly in a long game. in addition, they hold momentum very well against opposing balanced teams, because of taunt+wow (FUK FERRO). it's too bad, because neither of them have cofagrigus/dusclops's superb natural bulk.
jellicent is actually made of some tough stuff; it's hard to EV it well though because, as a bulky water, it needs defense, and as a spinblocker, it needs sdef (else starmie kills you). in addition subtox tentacruel beats you one on one unless you're a rest jellicent (i have seen this brought up seriously by skilled players, like yee. the man loves jellicent, ask him). i tend to run mixed EV spreads, aiming to not get 2hkoed by certain physical attacks (eg terrak stone edge) and then dumping the rest in sdef.
sableye on the other hand has no bulk whatsoever, but don't be fooled; this shit is good. i used to think it was crappy but wow it really impressed me when i took it for a spin in sand (heh. spin). taunt+wow is, again, incredibly powerful, and it's the only way to really "counter" ferrothorn on stall. i usually run a max sdef spread with taunt/wow/recover/utility. the utility move varies. i have had a lot of success with substitute against more offensive teams (first shown to me by temp v1), but i have actually seen sunny day sableye proposed once. sableye in sun is probably the only spinblocker in this game that does not lose to any spinner. i haven't tried sunny day sableye but it sounds too hilarious to pass up, especially on weatherless where you can bait out the weather inducer to die early.