I think a lot this ID-imbalance thinking comes from thinking only about the endgame, endgame items, and gears, as if nothing else exists until that time. Up until then, the IDs are all relatively balanced against each other, with each one being better for finding certain types of items than others. Nobody goes from Normal to Ultimate instantly unless they're extremely hooked-up with connections, or made a strong impression on people, or an alt of someone already well-established. It just so happens that some IDs are far better sooner rather than later, and Greenill is one of those, alongside Pinkal and a couple others.
For a relevant example, Greenill is absolutely fantastic for early rangers. They can obtain two of the three "blacksmith" rifles, Visk and Wals as early as Forest Hard (Hildebear and Hildetorr, respectively, at good odds.). Visk is a fucking awesome rifle if you're lucky with photon efficiency %s, while Wals offers a lot of power for similarly low requirements. No other ID can claim that until Caves, where both Greenill and Skyly can get a Visk from Pan Arms. Your odds as a fresh-faced player of killing a Pan Arms without high-powered-help are very unlikely without lucky instant-kills or massive time-expense with techs/traps and their separation/integration phases (Hidoom, Migium, and Pan Arms all have a separate drop). Visk is even a possible drop for Greenill only even on Normal difficulty (poor odds, but its definitely there!). Sure, they're not godlies, ubers, or anything even remotely close to that. But if you're just starting out as a ranger with nothing, however, they're extremely nice to have and offer an incredible power spike. They are also the only ID that can obtain a Justy rifle in Hard as a drop (Ep4, Astark). It's possible to get all of these through other means, but the cost generally isn't worth the result, and by the time these become available to all IDs, you no longer really need them. Furthermore, they can obtain one of those fancypants Justy rifles easily in V.Hard, again, earlier than any other ID in the game.
Does it suck for endgame-level equipment? Probably, I never took the time to research it. But I know from personal experience that it's extremely helpful to have a Greenill Ranger if you're starting from nothing, because they have very useful and very viable drops when you're on the ascension to greatness. Could it be balanced better with nicer endgame-level drops in suitable areas? Also probably, but the entire Section ID system was designed to get players to interact with each other, to trade or share items, to make friends with a variety of IDs with the goal of getting more items. Perhaps you should consider that, because it isn't worth re-rolling a character for the sole purpose of your section id. just start joining other people's games, or ask them to make one for you. Make an alt with an ID you'd like to have for later; you do still have more character slots than anyone could possibly need.
