They don't have a +2 bkdubs, the returning property on them is different and doesn't exist as a weapon special quality. It is a flat price added to the arrows. Same with the Bane thing. But otherwise spot on.
The goal is to turn them into a normal item. Why? Because it's Eberron. Not only are the gods different (is there even a NG archer type in there?), the gods are indifferent. So from a fluff perspective having belief based items doesn't make any sense (even if there were enough high levels to start making relics).
In that case I'd say up the price of them. Why? Because otherwise you are spending a feat or a spell slot to get. And note: mundanes CAN benefit from the bane part. Just ask yourself: is getting bane (anything you hit) on your bow worth just a feat? If not, don't take it. If yes, take it. If you want to up the power of the feat let it do something else as well. Also note: the bane part is the secondary effect. You only need to be a certain alignment to use the returning, and thus the awesome weapon bonus part of it.
It sounds like you just want this item, and you want it now. You don't care if it makes sense or if it's balanced, you want it.
From a mechanical perspective needing a feat to use a fucking item effectively is Epic Fucking Fail. Yes, you could use a spell slot too. But an argument can be easily made that's one spell slot per item (the feat at least applies to all). Have fun running out of Divine Power fuel in a hurry CoDzilla. Needing a feat to use an item effectively is a much milder form of Lich Fail, where you have to make the damn thing for a huge cost, then get crippled by LA. In other words, double whammied. Obviously it's much milder because a feat is less of a cost than 4 caster levels and all the associated goodies.
This is part of the relics mechanic. If you don't like it, change it.* But first: think about what a relic is. What it means. Relics are items (and there's more than just this one) that have an effect if you're the right alignment, and another effect if you worship the correct deity and spend a spell slot (usually 4th....rangers can do this btw...) or a feat. The first effect one makes it worth the cost and a little more, because of the alignment, like returning arrows (not actually the property, since returning can't be place on ammunition and doesn't bring it back to you no matter what), and the second one is worth a feat or spell slot, like the bane ability. Personally I think the Raptor Arrows are the best balanced one, with an appropriate cost for the benefit.
Now, working out the base bonus. +1 Returning is +2. Bane anything means +2 to hit and +2d6+2 damage vs everything. Obviously this is better than +2/+2. But how about +3/+3? +4/+4? This part matters because it determines how many slots are left (and how much it costs to enchant it, but that's trivial anyways). If infinitely reusable is a +2 (and that isn't that unreasonable actually considering the utility) that results in an arrow with 2-3 slots left.
This is just stupid. Bane (anything) isn't a weapon property I have seen in any book, nor is Returning Arrow That Goes to your Bow and Doesn't get Destroyed. The only weapon property on the arrows out of the box is +1. You have 9 left to work with pre-epic. This costs 3960 to make +10, so 9966/arrow, so for a full attack that's 59,796 for 6 (haste+rapidshot), or 49830 for just rapidshot. Added on to a +10 bow: 200,300+cost of the bow is 250,000 about for a +18 weapon, add in a level 3 spell slot for +23. Add in a feat or level 4 spell slot for a +23 with bane (everything).
*Change the relic mechanic for everything, not just this one specific relic.