I agree cover-negation is bad. But what I perhaps haven't said as many times is that it also kind of doesn't matter. Since 5E allows you to move freely both before and after making an attack, the practical effect is that anything short of total cover plays a rather small role in the game.
Move out of cover, attack, move back into cover (total cover) doesn't cost you more than a few squares of movement. And moving completely out of line of effect is so much more secure - chiefly because it protects you against many more spells than merely ranged spell attacks.
So while I can certainly see exceptions (open grassy fields with just patches of vegetation and low boulders granting half cover), in my experience cover-negation - while bad when it happens - is rathermore a theoretical objection, an objection of principle.
In blunter terms: the cheese of cover-negation is drenched by the cheese of peek-a-boo tactics, I'm afraid.
As for the range: I really have never come across a combat where the 300 feet range of Eldritch Spear hasn't been enough. Sure 600 feet range makes you into a true sniper, but again I haven't had the experience that suggests there's real power in this.
There are plenty of spells that would stand to gain substantially from a doubled range. Alas, almost all of those I can think of are spells with saves rather than ranged attacks...
Feel free to respond if you think I have misunderstood something