That change to alert is brutal, and honestly, I might ignore it since it cancels out all types of concealment giving advantage to the attacker.
I'm also ignoring the change to Glyph of Warding, because it breaks what I see to be the purpose of the spell. For example, my cleric placed a glyph of warding on a magic chest we found, which at the time was located on our boat. As soon as the boat left port, the box would have technically moved from where it was and the glyph destroyed. Even if it didn't, we needed to move the chest to a wagon some time later because we were going overland, and again, my glyph would have been broken, and then I might have to cast it everytime we stopped, because technically the glyph is moving with the wagon.
Heck, the SCAG and PHB hint that glyphs of warding are placed on spellbooks, I guess spellbooks that a wizard never moves from their pedastal?
I don't know what spell grenade exploit there is, but I'd rather deal with it if someone ever abused it rather than have my glyphs broken and made useless because the thief decided not to open the box until after they had carried it to the other side of the room