I agree that 250 heavy bombers utilised like Coastal Command did later in the war would be very usefull.
However, that doesn't take into account at least 50 of those would be in Fliegerschule.
That will leave you with 200ish left, of which
possibly but unlikely the majority could be dedicated towards naval reconnaissance.
Of course, just like with the Fw-200, you'll lose an additional few to flying the Fuhrer around and when Stalingrad and other calamities happen, you'll lose several dozens of them.
Anyways, with attrition those 250 bombers will be gone in several months.
Lastly, to get all 250 of these precious machines dedicated to naval recon and providing the Kriegsmarine with more success, you'll probably have to kill Goring too.
To put numbers into perspective:
Historically, the Germans built around
2000ish Fw-200s and He-177s, which failed to make much of a lasting difference to WWII, so I don't understand why you think a mere 250 will make much of difference.
But at first you said:
To which my answer was that there's no reason whatsoever to assume the Germans magically start producing aircraft efficiently and conduct their R&D in a sensible way.
My previous point still remains; without the 350 Ju-87's you'll at most have a little over a hundred conventional twinengined bombers, be they JU-88's or He-111 or Do-17's.
The German army needs close air support badly due to:
a) it's lack of artillery;
b) as support for it's fast, mobile forces for which regular artillery isn't fast enough untill you obtain large amounts of selfpropelled artillery.
b) isn't a problem in Poland, where the Germans fought pretty much a standard campaign.
Not building the Ju-87 is going to give a huge problem if the Germans choose the Manstein-plan in '40 for Fall Gelb; conventional horizontal bombing just isn't going to give the close air support the Germans desperately need which the much cheaper Ju-87 would give.
One last point; I'm not sure if the minor sacrifices you propose are actually as minor as you think they are.
IIRC the Do-17 was used for strategic recon during Fall Gelb. Without those to monitor the movement of the French armygroups, the Germans might have a lot less success then they did OTL. At the very least I'd expect a lot more timeconsuming panic-moments like the one Rommel had at Arras.