Starting Flask is the same principle as starting Cloth/5 in various top lane matchups, except Flask works in
every matchup and you have 75g change with which to buy a ward (or two more potions). It's plainly the strongest start for (every) lane unless you
really need boots form the get-go (gapcloser-less bruisers against harass-heavy ranged). Even so I'd say just wait for your first back, maybe even push the first few waves super hard so you can just recall and buy boots early without missing anything.
Long Sword/2 > Doran's Blade and should really only be gotten if you plan to all-in typical support/AD lanes at Level 2 and need the extra short-term power. Cloth/5 may as well be dead unless you're up against pure AD lane + pure AD jungle, in which case it's burst protection albeit still worse sustain. Boots/3 is obviously a lot weaker, with movespeed being moved out of boots into base speed, but it's still sometimes the best option for solo laners to dictate spacing and engagement against an opposing laner without boots.
tl;dr Flask rules. Flask/Ward/5 is basically "13 health pots" except it wastes less money and there's no downside to holding onto Flask as long as possible. Unlike potions, where you feel bad using them when they aren't "needed" (healthy but not 100%) or may end up never using them, Flask you can happily spam whenever you're below full health/mana with no consequence. And it's still perfectly good on manaless champions, although it's harder to justify starting with one then.
I generally like Flask/Charm(Bead)/2 on champions I plan on eventually building something out of the Faerie Charm or Rejuv Bead. Bead is honestly not that bad of an earlygame sustain item either, even if you're not building anything from it, if you don't want to buy so many potions on top of the Flask. It only costs you a net 54g, which in "health potion value" Bead regens in about four minutes and can stick with you much longer until you need your 126g back or the item space.
I can definitely see why [Thresh] would be used as a support, but I think I'd rather but his epic abilities to more use in top lane or even jungle where he can consistently harvest more souls.
Yeah this makes a lot of sense to me. Riot says they expect support to be a viable role for him but honestly you just can't give the guy an infinitely-scaling mechanic based on farm and think he's going to function best as a support. -_- And seriously if you think Sona is squishy now, imagine if she didn't get up to ~60 Armor from Level 1 -> L18 and didn't have an Armor/MR aura. ;[ I don't see it working unless he has absurd base Armor/Health, which would probably just make him a broken solo laner.
My fear may be abated, however, if CertainlyT's initial post stating "enemies that die
around him sometimes drop souls" is an indication that Thresh merely has to be nearly for a chance that enemies drop souls and not necessarily kill them himself.