Yosef, this really is a very interesting question!

1. The Bach (Rav Yoel Sirkis) in his commentary on the Tur (OC 25:5) asks your question, without making reference to our Gemara concerning Chanukah. He asks, why is Tefilin different from Sukah? We say the Berachah, "Leishev ba'Sukah," because the Torah commands us to dwell in the Sukah, so why do we not say the Berachah, "Likshor Tefilin"?

2. The Bach answers that the primary Mitzvah of Tefilin is that we should wear them all day long. (Nowadays, we do not do this because we are unable to ensure that we will have the right thoughts all day long when we are wearing Tefilin. Mid'Oraisa, though, if we would be on a sufficiently high level to be careful with their holiness, then we would be required to wear them all day.) The Bach writes that if we would say "Likshor Tefilin" -- "to tie Tefilin" -- this would imply that if one ties Tefilin on his hand and head for one moment and then he removes them, he fulfils the Mitzvah. This is why the Rabanan decided that one should say instead, "Lehani'ach Tefilin," which implies that the Tefilin must rest on us for a significant amount of time, such as an hour at least.

3. I would like now to attempt to fit this idea of the Bach into our Sugya. When we look at the way Rashi explains the other opinion here, that "Hanachah Osah Mitzvah," we notice that he writes (22b, DH v'Iy) that this means that the primary Mitzvah of the Chanukah candles depends on setting them down in their place. Rashi (DH Ein) also writes that according to this opinion the actual lighting of the candles is not the primary Mitzvah. This implies that even according to the opinion that Hanachah Osah Mitzvah, the lighting is also a part of the Mitzvah but it is not the main part.

4. I would suggest that something similar exists with the nature of the Mitzvah of Tefilin. Tying on the Tefilin is a part of the Mitzvah, but it is not the chief part. Tying is a "Hechser Mitzvah" -- it enables one to do the main Mitzvah, namely that the Tefilin should be "Munach" -- "placed" -- on our bodies, and this is the reason why we say the Berachah, "Lehani'ach."

5. It seems to me that according to the opinion that Hanachah Osah Mitzvah, the Berachah one makes is "Lehani'ach Ner Shel Chanukah." This is why the Gemara is able to prove from the fact that we do not make the latter Berachah, but instead we say "Lehadlik...," that Hadlakah Osah Mitzvah.

6. In the same way, the fact that we say "Lehani'ach Tefilin" proves that the most important part of the Mitzvah of Tefilin is that we should wear them, and it is not sufficient merely to tie them on for a moment.

I think that this important question deserves further thought but I will close here for the moment.

Kol Tuv,

Dovid Bloom

Here is a different reason, given by Teshuvos Maharit II, Orach Chayim #7, for why the Berachah is "Lehani'ach" and not "Likshor."

Tosfos in Menachos (35b) in the name of Rabeinu Tam says that the verse in the Torah, "And you shall bind [the Tefilin]...", is referring to the knot that attaches the straps of the Tefilin to the houses of the Tefilin. Since there is no Mitzvah to tie the straps of the Tefilin into the boxes every day, it follows that one cannot make the Berachah "Likshor" every day because one does not perform this Mitzvah every day, but rather only when one prepares the Tefilin at the beginning of their use. This is why we make the Berachah "Lehani'ach" because the Mitzvah every day is to place the Tefilin on our arms.

Kol Tuv,

Dovid Bloom