I'm with the consensus here, I'm afraid. This is skillful but deploys that skill so unambitiously that I can't get too excited about it.

I am afraid that I have to join the negative chorus. For me, "oast" was the only redeeming feature. One problem is that there is no indication of why the victim of this attack is deserving of such treatment: Shakespeare makes us feel passion and joy; this is too much of a rote exercise to make us laugh or feel anything.

I'm another. It's unambitious, gimmicky, not up to Bake-Off standards.

I enjoyed it, harmless, but I'll read Wendy Cope anytime.

Parody
 

This is a very well-executed parody, worthy of Marcus Bales.

Life is unfair and swiftly it declines.
The Yuletide yew we hewed remains untrimmed

I think those lines are good, the first for pithiness and the second for sonics.

But the rest is a fairly weak repurposing, which (as others have been saying) doesn't do enough that's clever or unexpected.

First, thanks to aka Orwn Acra (sp?) for comparing said parodied sonnet of the Bard's with this pretty number.
After that, Shakespeare proved his love far beyond a summer's day, whereas this sonneteer seems content to merely liken the season invoked and former lover.
Other than that, I could wish it a tad more generous in differing with Shakespeare's but that seems rather peevish.
L7 introduces what follows, yet seems to stand alone as it cuts in after the flow of the previous lines.
If it's not rude, I beg to differ with the "impeccable craftsmanship" assessment, the flow rather choppy, which is typical of an amateur, the Bard being no exception.
Elsewise, this is a clever piece of work and I rather enjoyed its parody of sorts.