Imbagon vs Ranger (Barrage + Save Yourselves)

the ranger only can only have 2x adrenalin 50% of the time (For Great Justice) compared to the paragon's 100% of the time (FGJ + FA)...The advantages I see with the imbagon are the lack of reliance on enemies grouping up...and the PVE skill 'There is Nothing to Fear'. As to the initial Ranger vs Paragon debate, you just hit on 3 of the 4 largest issues right there, the 4th being energy.

First of all, Barrage only hits adjacent targets, so you must have balled up enemies to be sure of gaining that adrenaline during the downtime of "For Great Justice!"

To keep SY up 100% of the time in a fight, the Paragon must hit 4 times within 6 seconds throughout the fight, which can be done without IAS (4 x 1.33 = 5.32 seconds). This allows a margin of safety if you don't happen to hit SY the exact millisecond that it recharges and even allows for a miss now and again should you throw in some IAS.

For the Ranger, for 20 seconds out of every 45, you would also need to hit 4 times within the same 6 seconds (which is easy enough to do with either Barrage or, heck, normal attack with enough IAS). For the other 25 seconds, however, you must hit 8 times within those 6 seconds. That requires hitting about 3 enemies each time you press the Barrage key (remember the 1 second recharge on Barrage). Doable, but it allows no room for overlap unless you help things along with an IAS or more enemies ball up, requiring fewer than 3 Barrages.

Secondly, TNtF is not the showstopper that SY is, but an additional 35% damage reduction for the whole team (including the Paragon), 50% of the time, plus a party-wide heal every 20 seconds is a nice add-on that the Ranger just couldn't provide.

Finally, energy. Almost no energy must be expended to keep everyone safe as a Paragon, beyond the 2 adrenaline-gaining skills. For the extra IAS of Aggressive Refrain and a margin of error, a shout affecting the Paragon ending once every 20 seconds or so is also needed, which TNtF can also fill the role of. In the meanwhile, the Paragon should be gaining 6 energy every 4 seconds by spamming SY. This allows for extra energy for whatever additional support/damage skills you want to take along.

For the Ranger, 2 energy per Barrage plus the occational 5 energy for FGJ pretty much uses up the Ranger's energy regeneration. If you throw in an IAS available to you, you must expend more energy. Expertise only reduces energy amounts spent, it doesn't provide any net gain like Leadership does with many shouts and chants. So unelss you have a Zealous bow (another conditional, which also means you must not miss/be blocked too many times to make up for the -1 energy regeneration) or a party member with some sort of energy gain skill for you, you end up with a net loss. Over a few cycles, things start to slow down while you try to maintain energy, and you begin to lose ground.

Don't get me wrong, Rangers are good for SY spamming, and can be an asset to the team. They are especially great early in the fight, as you mentioned. The main difference, though, is that the bow-wielding Ranger is reliant on more circumstances than the Paragon and thus not as guaranteed to be able to upkeep SY constantly.