In a word, yes. If you want more words, keep on reading.
First off, I don't like the word patter. Patter is defined as "to say or speak in a rapid or mechanical manner; to speak or sing rapid-fire words in a theatrical performance." I prefer the word "presentation."
From a techincal standpoint, it makes sense to practice your presentation when you practice your sleights. Often, beginning magicians will pause when they do a sleight. Talking over a slight is the best cover and the easiest way to do that is to have what you are going to say memorized.
If your presentation has say-do-see patter (in this case it is patter) where you say what you are going to do, do it and tell the audience to see the result (what Eugene Burger calls "narrating the adventures of the props") you really dont need to reherse that. Actually a lack of rehersal leads to that type of presentation because you have nothing else to say.
If you want to go beyond talking about what you are doing with your props, you need to script your presentation. The presentation provides a context for the effect that the audience is seeing. It draws them in and gives the effect somemthing more than the adventures of the props. A torn and restored card effect can become about how, no matter what happens in life, we are able to pull the pieces together (a simplistic example, but illustrative nonetheless).
I do an effect where a card vanishes from the deck the spectator is holding and appears in a previously empty bottle another spectator is holding. My presentation is about my Uncle Jim who, as I explain, would go into his basement every night, open a small bottle of gin and study magic. Uncle Jim wanted to develop an effect where a bottle disappeared and appeared right next to the selected card in the deck -- a good trick that never worked because Uncle Jim got it backwards.
I do Eric Ross's Election as a compatability test for couples asking if it is better to be the same or different. I do a routine using worry stones that talks about the essence of worrying and philosophy of prayer quoting Jewel, Ivan Turgenev and Søren Kierkegaard. I do Juan Tamariz's Paradise Recovered as a cathartic experience in letting go of the things that hold us back in life. I love Wayne Houchin's Houdini's Influence which has a wonderful presentation based on the the deck of cards Houdini used at his last performance. Also, Google Marc DeSouza's Curse of the Rasta for another great example of a fun story.
I do some effects with say-do-see patter, mostly when I'm playing around with folks (my Omni Deck routine) or doing a routine that doesn't lend itself to a greater context (e.g. Bannon's routine from Six.Impossible.Things). However, for my performance shows, everything is scripted and rehearsed.
Yeah, you'll get used to that, I am almost convinced he is 200 years old, his knowledge base is just too large.
Equate age with wisdom should you not.
Unless you're a really great actor, having a script line for line will seem too choreographed. From my own experiences, I think it's better to have a few lines you really want to hit, but the rest be improvised. This will leave the audience with the feeling of a more unique experience. And since you said you excel at improvised comedy, this shouldn't be too much of a problem.
The key is to have the script memorized but to perform it in manner that makes it seem like you don't have it memorized. Also, you should perform in a way that allows you to improvise. In one performance, in response to me stating that the card was going to disappear from the deck and reappear in the bottle, a spectator said "there is no way he is going to do that." I had her repeat it into the microphone, gave a nervous look and said "right now, I'm thinking the same thing." Magic is one of the art forms where the audience can become part of the presentation. I've seen performers ignore what the spectator says and just keep going with their script... ugh. Now, I mostly perform parlor style magic. My presentation has more of a theatrical quality to it and a well scripted presentation is more necessary.
However, I view close-up magic as a conversation. Have you ever noticed that most conversations are a combination of questions, stories and people expressing ideas? For my presentation for close up effects, I try to make it a conversation that the spectator participates in. In many ways it is scripted but I'm also able to go off script if the right circumstances present it.
