TL;DR: No compelling reason I can think of, since the proposed approach strongly contradicts some main plot drivers story-wise; AND the map points to the Temple already (not to Luke - see #3 below) fact-wise.
Actually, sorry but your ideas contradict what the plot says, sorry:
It would explain more compellingly why the First Order/Kylo want the map. It includes all the reasons they have in the movie (going after Luke) but includes a more compelling, at least to me, of wiping out all traces of Jedi from the galaxy
Snoke very explicitly said he cares very much about (Resistance NOT) finding Skywalker. In the novelization, he orders the immediate destruction of Resistance base on D'Qar, for one and only reason: to prevent them from having enough time to send the ship to find Skywalker.
And there would be no threat of Skywalker’s return today. {{about Vader's failure}}
and from WGA script:
> SNOKE (V.O.)
The droid will soon be delivered to the Resistance...
SNOKE
... Leading them to the last Jedi.
If Skywalker returns, the new Jedi will rise.
and
Snoke cut him off. “We cannot wait. Not even for hours. Hours that may permit as little as one ship to depart with the information that will allow them to find Skywalker. That would be one ship too many. The more time we give them, the more likely the chance, however slight, that they will find Skywalker and convince him to return to challenge our power. As soon as the weapon is fully charged, I want the entire Ileenium system destroyed.”
We don't yetr know quite why Snoke is so concentrated on Luke, other than he's the last Jedi Snoke knows of.
However, I suspect that further films will reveal that and it would be meaningful to the plot.
It explains better why the Resistance cares about the map. It still is to me a weak reasoning, but again including the first Jedi Temple into something they want to find makes more sense than a person who ran away
Resistance - specifically, Leia - very explicitly is looking for Luke.
Opening crawl:
With the support of the REPUBLIC, General
Leia Organa leads a brave RESISTANCE. She is
desperate to find her brother Luke and gain
his help in restoring peace and justice to
the galaxy.
Tekka explicitly talks about "Without the Jedi, there is no balance to teh Force" about finding Luke
And the ending of the script explicitly talks about Rey coming to Luke as "Galaxy's only hope"
IT IS LUKE SKYWALKER.
Older now, white hair, bearded. He looks at Rey. A kindness
in his eyes, but there's something tortured, too. He doesn't
need to ask her who she is, or what she is doing here. His
look says it all.
In response, Rey pulls something from the pack.
LUKE'S LIGHTSABER.
And she holds it out to him. An offer. A plea. The galaxy's
only hope.
It explains why the map might exist in the first place (why is there a map of Luke's location that both sides have access to part of? what?)
That's already the case and explained via WoG in an answer - since R2-D2 downloaded the map from Death Star computer (what are they, running a torrent site? Why was the map there???) 30 years ago, well before Luke went there into exile.
However, the phrasing about "Map for Finding Skywalker" - while inaccurate in-universe - serves the main plot lines much better