Hello Mikko,
I think William is one of those classic names that is pretty much free from stereotypes.
A William could be a jock or a nerd, big or small, ugly or handsome, etc.
Willem and Wayland are nice and unique names, however, the trouble with names like these that the majority of the population have never heard of, is that you will introduce yourself...
and then you will have to introduce yourself again and again to the same person.
It'll go something like this -
"Hi, I'm Willem." <shakes hand>
"Pleased to meet you,
William. I'm Peter."
"No, not William, Will
em."
"I'm sorry, can you repeat that?"
"Will
em."
"How do you say that?"
(Peter trips over his tongue several times in his attempt to pronounce the name, finally gets it on the 5th try.)
"Oh, Will
em. How do you spell that?"
"W-I-L-L-E-M."
"Oh, heh, heh, just like it sounds."
(Through gritted teeth) "Yes."
"So what is that? Is it French?"
My surname is extremely rare. I've had this exact conversation (names changed), in that exact order, everyday, multiple times a day, my entire life.
It gets very tiresome.
It's going to be difficult enough implementing (to use your word

) your new name, try to make it a recognizable name that people at least know how to pronounce.
Unless of course, you love the name enough to go through that everyday.
By the way, I really like William, and Will does sound sexy.