As always, theres pro’s and cons. Personally I think the cons outweigh the pro’s. For starters it’ll commercialise Madinah to a completely new level, pilgrims will often be tempted to ‘shop till they drop’ instead of spend their days praying & giving salaam to our Rasul & his companions.
Those that have been to Madinah will know the peace and tranquil atmosphere they experience, however with these massive skyscrapers towering over Masjid-e-Nabawi this is bound to disappear.
On the flipside, this could be one of the signs of the Last Day. As we all know that when Dajjal (the antichrist) arrives, he will torment the earth but never able to enter Madinah or Makkah. By this logic, thousands of believers will flock to these two cities to avoid facing the trials of Dajjal. Hence with the massive developments, perhaps this allows Madinah to accomodate this influx of people.