Today there is more attention put into preamps of interfaces, which have been of mixed sort in home studio level gear. For example the preamp in my current interface Propellerhead Balance is either really bad or defective. I'm not being picky here, it's unusable for things like recording an acoustic guitar. It's so sad, because I like the functionality and everything else about Balance.
Another problem I think in situations like this is that in many interfaces line inputs are routed through the preamp. This is somewhat understandable, because it gives more input for those sources that don't have it enough, and there are lot of them. The downside is that you can't use external preamps to a) get different kind of preamp sound or b) bypass the extremely poor preamp of the interface.
Some interfaces have extra line inputs which don't go through the preamp, but it seems to be quite rare technology used in consumer level products you would expect to find in home studios.
So now when I'm trying to find a new interface I've also noticed that for whatever reasons many interfaces don't have the direct output button in the front panel. Sometimes it's mentioned in the mixing software, but sometimes it's really hard to find out if there is direct monitoring in the device at all. I find that frustrating, because no matter how low the roundtrip latency is you simply need direct monitoring in real life recording.
I think what is sorely missing right now is a decent interface without preamps and with quality construction and A/D-conversion so that you can buy whatever preamp(s) you want and then use the interface simply to convert the analog sound to digital and forget about shitty preamps they have to use in interfaces to reduce the price.
Also I don't like the way they remove important controls from the interface and put it into some kind of control/mixing software. I don't know if I'm exceptionally difficult person, but I find it difficult to find proper gear to replace Balance in an affordable price range. It should be either an interface with good preamp so I don't need an external preamp, or less expensive interface with direct line in to use with external preamp.
I guess we live in a world where manufacturers have to be careful not to create the kind of equipment which you can easily extend and use years without problems. This is particularly true in home studios which has been a growing market for last ten years at least.