funny thing is I usually see 2400 pros go shureyas asap although I guess so that they can clear wards with oracles faster and have the team initate ability
also I totally forgot about 9/0/21 build. do you use mpen marks with it too or just go all armor?
and I meant I don't have more HP with just locket vs aegis+hog
good guaranteed initiation is really good at their level for the teamfights at dragon
however in normals and sub plat ranked you barely ever see those happen with any frequency and the speed boost isn't really needed. people tend to play more passively, so you get more bang for your buck stacking wards and getting offensive jungle sight.
also with all supports, i use armor reds. they don't scale well enough for any of the good red runes(mpen, arpen, ad, etc.) to actually remain useful, so armor just works better for what they need to do.
How often do you guys find yourselves going Locket? I almost never do, always going Randuins instead.
always go for locket. has an additional passive aura, which is nice, but more importantly, the tanky dps or the jungler almost always buys randiuns anyway. many tops and jungles buy hog, and they have the income to actually afford randuins whereas locket is a much more affordable option for a support.
as an example, normally i go philo -> hog -> boots 1 -> aegis -> zeke's -> locket -> shuryela's(of course i end up switching things around almost every match but this works best for the example). if i bought randuins instead of locket, i would probably not be able to afford shurelya's before the match ends
locket active will also win you teamfights by inching your carry alive through ap burst