I believe Heartland Conqueror works in Ravenwatch, but Order's Wrath does not. Neither do most monster sets. So I guess you are not playing in Ravenwatch. I don't rate Heartland. It may be decent in Ravenwatch. Outside of that, meh. You can go front bar Sharpened, back bar Defending or Powered. Some people swear by that, but I think when you compare with other options in UESP, the set is average to below average. The fact that you can back bar a set, front bar a set, fit a monster set, a mythic and 1x Trainee, any such setup with meta sets beats Heartland outside of Ravenwatch, since Heartland needs to be double-barred or there's no point.

Order's Wrath kind of makes sense on a templar, but it is more of a PvE set at the end of the day. Try something more meta, such as Rallying Cry front bar, Wretched Vitality back bar, Zoal monster set, 1x Trainee and mythic of choice, e.g, Markyn, Wild Hunt or Sea Serpent. Don't forget to build for spell damage, not weapon damage, and make sure to activate the Minor Sorcery class passive. Experiment with a combination of heals, such as Honor the Dead, Rally, Resolving Vigor, Extended Ritual and Draining Shot. You will need 3 to 4 of the above heals in the build.

I do not recommend Pariah. It's so yesterday. It hasn't felt good to me for a number of patches. If it has to be a set like that, try Mara's Balm. That said, I would wear predominantly medium to get your damage and sustain up. This also fits better with a bow rather than wearing heavy.

For a more aggressive option than Zoal, maybe try a Blackrose Bow with Draining Shot, if you have that. Nothing like healing and keeping up the pressure at the same time. Using an arena weapon and, say, Rallying Cry on the other bar opens up the option of wearing another 5 piece on the body, e.g. you could go back to Heartland, if you're married to that. Blackrose Bow, Master Bow, Vateshran 2H (front bar), even something like a Vateshran ice staff would all work, with Rallying Cry on the other bar and, say, Heartland on the body. This leaves room for either a monster set or 1x mythic and 1x Trainee. Monster sets that work include Zoal, Bloodspawn, Balorgh, perhaps Zaan.

Should you be tempted to return to Pariah, I would say try Mara instead, double barred. In that case I'd find it hard to recommend pairing with Rallying Cry on a stamina class playing a bow, since that will limit the amount of medium armor you can wear. I'd probably go for Mara jewelry and 2x to 3x Mara on the body (depending on mythic), then back bar an arena bow and front bar something like Deadly, Plaguebreak, Nightmother's Gaze (crafted) or your Order's Wrath.

If you do want to stick with Heartland Conqueror I would suggest considering running DW with Nirn/shapened. Most traits get cut in half on DW but if you run Nirn you get the same 30% percent boost as with 2H weapons on the main hand and then nearly 3K pen from the off hand.