I used to do kendo (got to 2. or 1. kyu - can't remember). It took me quite a while to 'unlearn' my kendo-habits, when I took up Aikido. Kendo is a linear, competition-sport which (until you reach a higher level) encourages a certain amount of agression and a focus upon winning. I sincerely enjoyed the paired kendo-kata, which bare some resemblance to the ken-tai-ken techniques of Nisho-senseis aikido, but in the long run the endless row of fighting with all the gear on, made me realise that I'm not cut out for Kendo. I would NOT reccomend anybody to do Kendo in order to improve their Aikido. At least not until they know so much about Aikido that they can keep the two things apart. But please remember that I'm proficient in none of the two arts.
There ARE some things which are mutual for Kendo and Aikido, especially with regards to recieving an attack, but the fact that an Kendo-ka would be much more prone to initate an attack than an Aikido-ka suggests that other arts would complement Aikido much better.
Like many other I believe that Aikido is based upon sword-work, and so is Kendo. However the two arts have evolved in two very different directions as far as I know.
I hope you can use this.
BTW Fiona: if that's the style of cutting that you have seen, then I am quite puzzled. That's not the way we learn to do bokken-suburi in the aikikai-dojo I practice in.