The basic vertical and horizontal chops I have seen them doing require a lot of movement before they land. Also due to it being similar to a slashing motion, it's much easier to block because of it's angle. In contrast, most boxing punches act more like thrusts that are quicker and harder to block because the vector of the attack is more like a point rather than a line.
Also keep in mind that aikido strikes simulate weapons attacks as well. If you watch a shomen or yokomen attack and then hand them a sword, generally
, the shomen and kesa cut should look pretty darn similar to the strike they did before.
Where as, boxing is an empty handed fighting style. As far as I am aware, none of the principles are based on a weapon (other then your fist I suppose) It is my impression, like you said that for the most part, the attacks are fairly straight and/or compact. Sure, obviously a cross, upercut, etc require some directionality, but the principle behind why the attacks are that way is different from some aikido attacks. You could dabble further into it and say that even a boxing jab is on a straight line, just a horizontal one.
Another point is that, until you get better, you need your uke to let their attacks hang out there a bit. It's hard enough to work on something new when they are kindly leaving their hand out there for you. Imagine how long it would take you to work on a technique when they keep retracting their punch and your left grabbing air.
With that said, just soak up what you can and you will come to your own conclusion. You will find things you like and you will find things you don't (I have). In the end, if you train long enough, your aikido will look different then others, though the foundation and basic principles should be the same.
I guess you could think of it like walking. Everyone has the same basic foundation and principles needed for walking, it's just some people use a different gait that suits their body. I feel that it is the same thing with aikido. Change a bit to suit your body, but change too much and you are doing something else entirely (not that it's a bad thing, it's just not aikido).