Hey there - I am a Support Main @ Gold/Plat levels that has a habit of playing off-meta supports, I know the ins and outs of what you need.
Some off-meta supports that are pretty viable right now:
Generally, as a support you'll want to control the lane with either harass or threat. You'll also want to look at scalings, item dependencies, and sustain/shields.
1.) I dont want Blitzcrank to hook me, so i'll stay away (Threat!)
2.) I'm low on health from all this Xerath harass, so i'll stay away (Harass!)
Let's break him down....
HARASS: 1/5 In terms of harassment I think he's very low on the spectrum. His only potential damage tool that isn't melee is his spinning slash, and it puts him at significant risk - especially early game. It will work against BAD PLAYERS, but by the time you hit gold, I predict you will get harassed out of lane.
THREAT: 3/5 He does better here; with his shout slowing enemies down, and the risk of him spinning into the adc, this could get ugly quick - but this falls apart if he's low on health. He will lose especially bad against poke supports with reach. The AD loss the enemy suffers doesn't mean shit when your sitting @ 40% health.
SCALING/ITEMS: 2/5 Eh. It's pretty rough here too - if you don't snag a kill, your left with very little gold - your items and mid-game spike will be moot, and you won't be able to provide much of ANYTHING to your team.
SUSTAIN/SHIELDS: 2/5 Also pretty bad here - He has a bit of HP recovery and a solid ultimate, but his early laning phase is going to be a nightmare against a competent strong support. Lord help you if they bring a Caitlyn against you.
Sooo.. Out of a possible 4 to 20 points, he scores about 8. That's pretty bad. I would classify this as a 'troll/experimental' pick AT BEST. If you really must, make sure your ADC has mobility. What it comes down to is control - he doesn't have enough of it. If he gets poked, he just kinda loses and has no answer.
If your looking for a 'melee brawler' archetype to take support... I'd recommend one of the following, as almost every single one of them offers more to the support lane than your Trynd:
