I like my 3 iron better than a hybrid for that spot, but my 17 degree is indispensable. Maybe for you that 20 degree will be a wonder club, depending on a number of factors. I only carry the 3 because I can do anything I need with it and I like the feel and price of irons better. There's no such thing as "workability" in my book; I think that and "feedback" are left handed compliments you say about really nice clubs you like but can't hit. I've never had trouble curving the ball with any club and if I miss the sweetspot I can tell even if it's a forgiving club.
I like the gapping I get and I do carry my 3 iron farther than my 4 by a good bit, but for many the two will wind up about the same. If you feel you need a particular distance, an adjustable hybrid is a great idea since you can fine tune the length and loft to within 5 yards or so of your target distance. Wanting a club for extra distance at that range is smart, since we don't finesse 200+ yard shots as often as we'd like. My 17 degree is a very long club and I could use it as my only fairway wood slot or not hit much farther than my 3i depending on my needs.
If you feel you can't hit the iron high enough or the trajectory isn't ideal, you'd do well to try the hybrid. I can hit the hybrid higher than anything in my bag off the tee, or I can knock it down and get roll. Off the deck I can still hit it very high but I can hit the 3 iron high enough not to need a hybrid to help. For you that point in your set is probably a 4i, especially on off days. I find that I never struggle with the 3 off the tee but some days I have trouble off the deck with certain shots. It may be worth it to have the hybrid for times like that if you aren't constantly working on your swing.
If you feel your accuracy or contact isn't good with it, you're on your own with that one. Of all the factors above, I'm assuming your swing isn't the issue but mishits and wide dispersion won't be helped by a longer shaft. 3 irons are somewhat hard to hit but if you're making good contact and using good mechanics the hybrid will not be noticeably tighter even though they are labelled as being more forgiving. Maybe they help on off center hits a bit because of bulge and roll, but launch and distance are the key advantages to hybrids as long as the specs fit you equally.
As far as picking one out, my only suggestion is that these kinds of clubs are personal. Pick one that has a shaft you like or buy a shaft and I suggest you regrip it, get the length and weight adjusted to your liking, and make sure you like the look of it. I hate 90% of the woods on the market because of superficial crap like how they line up or how they sound, but if you find one that you like it's a godsend. There's a lot of talk about hybrids that hook too much, for example, but it's typically operator error and lack of familiarity. There will be a few that you naturally line up and hit pretty straight or just suit your swing, and you won't be happy if you go against that first instinct. In my experience, once you want a specific model of something like a golf club or a car, settling for a similar one doesn't work.
Personally I like the more wood shaped models best and I like Adams, and I really like slot technology. After hitting it a bunch of times, I can trust my hybrid to do what I want and I can align it well on all sorts of shots. I also like my hybrids to swingweight slightly lighter than normal, in the high C range because they're a bit easier to swing with good timing, especially when I'm hitting them full speed. Alternatively I could shorten them slightly but I don't want to mess up one of my favorite clubs.