Although I've not done Taekwondo much myself I pretty friendly with the local Taekwondo instructor who teaches at the same dojo, and he also came along to aikido for a while.
I expect much of it depends on the 'style' of your taekwondo and your teacher. Obviously there is a lot more kicking and punching, but I don't think this is a bad thing (as it is useful to know for aikido anyway). However there are also many locks, pins and throws which are very similar to aikido (e.g. ikkyo, nikkyo, wing-holds etc). Some of them are a bit more complex and the blending motion isn't as evident. In fact I've come to believe that at advanced levels a lot of martial arts contain very similar techniques. Therefore it may depend on whether you are taught these early on, and whether the instructor is advanced enough to have a comprehensive knowledge of these things.
It is also my contention that aikido isn't about the techniques, its about the principles of blending. Therefore you should be able to incorporate your aikido into your taekwondo without too much of a problem.
The only thing I found frustrating when I did karate is they didn't like me moving off centre line or turning my hips to avoid a blow, but instead they wanted me to block. I realised this wasn't a style I liked and so I left.