I agree.
The problem is actually twofold.
1. Coinbase has adopted a very poor pricing scheme. At least it is in my opinion, in light of the fact that you are far from the first person to object to this or to make this observation. It is only a problem because of number two:
2. People have an expectation, and then Coinbase goes and quotes people something like 804 or so for sell and 808 for buy. This is stupid, because that's not their actual bid/ask spread. Their actual bid/ask spread is quite a bit wider, as you noticed.
So firstly, because of the way they function, why is there even any bid/ask spread at all? They should just quote 806, and then let the fee be what it needs to be for them to function as a company. Alternatively, they could let the entire thing be handled via a bid/ask spread and quote you something like 821 and 794. The combination of having both a bid/ask spread and a fee just confuses and frustrates consumers in my opinion. I also find it to be a little bit disingenuous. The only reason to ever be concerned with having a different buy or sell price is when you need to compare how much you might be buying or selling, and how that changes the price.
I've been frustrated with this pricing model for a long time, and also have been extremely frustrated with certain aspects of their service as well. I've had many many orders go through with no problem whatsoever, and I've also had a couple that didn't. No particular rhyme or reason that I can see other than The standard conspiracy of the price was rising faster than expected and so at the very last second, the day that I'm supposed to receive credit for the bitcoins, my order is canceled. Total value canceled, about 80 coins. Each time reaching out to support got no reply, until days later when I submitted a "wtf" post to Reddit. I immediately (within 15 minutes) get a reply that they would fix the issue and then nothing further (beyond their promise that my account was "whitelisted"). I'm pretty sure that overall they mean well, and they're better then most of the alternatives for many people. Without any competition they're not forced to improve any further. But I can't say that I'm happy with a certain amount of Mt. Gox-like behavior that I see.
And I'm certainly not happy with the zero warning change to the way they handle instant purchases. It'd gotten to where I would not purchase more than 10 Bitcoins at a time because I could no longer be confident that larger orders would actually appear at the price that I bought. Now that they have lowered their weekly instant limit to one Bitcoin, their services frankly largely useless to me. They stated that they intend for this to be a service that allows you to buy just about any amount you would need instantly to utilize most merchant services. That's fine. It's certainly good for that, and indeed a few times I've used it for exactly that. But I'm afraid this is no longer my service of choice for buying larger amounts of Bitcoin.
It's kind of unfortunate, because the service that I have been in development of had agreements with a couple exchanges, a couple institutional minors, and of course Coinbase. Having to adjust the way the service will work with Coinbase written out of the equation has delayed my development of it. But it has also changed my thinking regarding the services that it will offer, in order to meet what I have identified as a market need for a legitimate competitor (and of course I believe an improvement) to their services.