Interesting theme this week.  More challenging than most.  Clever, too.  I’d suggest filling in as much of the puzzle as you can before trying to work out the theme.  For that reason, I’ve reversed my usual order and put a few specific hints first:

It may be spotted in a pet store:  “spotted” isn’t exactly what these animals are.  Think common house pet, not exotic animal.

Hinders:  It’s a legal term for it, though it sounds like something that would definitely slow you down.

Wife of Woody:  Allen, not Guthrie

Fancy Flower holders:  they can also hold coffee or your great great grandfather

Biblical resting place:  Two words, the first is an abbreviation

Without any oomph:  I was thinking TEPID, but it’s even more exhausted than that.

Well-rounded:  This kind of well-roundedness isn’t the kind that makes you attractive to grad schools.

Old barnstorming needs:  How’d these folks get to one out-of-the-way place to another quickly?  2 words

Really hurts:  And causes some lasting damage.  Literally hurts, not figuratively.

Something media execs have their eye on?:  The key word in the clue is “eye.”  Note the question mark indicating that it’s a bit of a “wink, wink”

Source of talk often:  Two letters followed by a word.

Theme:

We have a bunch of dashes with no clues. Hmmm.  By doing the “crosses” (words that transect the “dashed” clues), eventually we get some words that don’t seem to have much to do with each other (and, don’t sweat it, they don’t have anything to do with each other, at least not [the answer to 108-Across].   But what else is strange about the puzzle.  Well, let’s take 6-Down (“The Pied Piper of Hamelin, e.g.”) Hmmm.    Can you think of any three-letter word to describe the Pied Piper?  No, I can’t either.  So let’s look at the crosses:  “Break in poetry.”  If you don’t know poetry that might be difficult, but it’s some kind of gap and probably Latin.  Maybe you can guess a few letters.  Then check out “The hare, notably.”  Well, compared to the tortoise, what was the hare.  Well, the LOSER doesn’t fit, but there’s a two-word phrase that means more or less the same thing.  “Allowed aboard” is another two word answer that’s pretty straightforward.

So now do you have 6-down?  If not, here’s a hint:  If the Pied Piper were one of these, he would be renowned as the greatest traitor of all times.  Now notice that you have one of those dash clues just below it.  And what does a dash do?  Maybe everything’s not hunky-dory or easy-to-answer, but you get the idea.  Ok.  Now go for a few of the letters of 42-Down.   So what was the Pied Piper?  And what’s the theme title?

Got it? If not, try work around the other “plus signs” found in the design of the puzzle itself.   As soon as you get one, the rest will fall nicely in place.