It's a conversation, it doesn't require agreement/disagreement. This is not game of who wins or keeping score. What said was contesting that its broken, and agreeing that its a lot of resources spent for the gain being so situational. So it doesn't matter so much how you calculate it since it will rarely matter. That being said, giving it 1200 ft is not broken so I would be fine with it at my table. The exception being that if they also have permanent flight.
It isn't about keeping score or anything, it is about understanding
why you quoted me. Most times IME if someone quotes me it is either because they agree and are reinforcing the points I made, disagree and contesting the points I made, or using my points to further the general discussion. In this case you seem to be doing both in one post--contesting one point but agreeing with another...
Since you are contesting it is broken, claiming it isn't, but then appending a condition (flight) when it could be broken, that to me implies it
is broken. As for the flight issue, it doesn't really need to be permanent (
Fly alone lasts 100 rounds) and 5E does have a playable race (Aarakocra) which does have permanent flight as well as Sorcerer sublcasses (Draconic Bloodline and Divine Soul) which allow permanent flight (albeit at level 14...
shrug).
My point was (as was yours it seems), broken or not it requires a lot of resources to get there and is overkill since most combats don't even begin at that sort of crazy range. FWIW I said I am fine with it as well, consider it overkill, and if the player wants to expend all those resources for it, go nuts.
In our CoS game my sorlock only had Spell Sniper and that alone helped make one encounter easy when it should have been hard. Once our party took the high ground, the earth-bound foes were being picked off left and right before they could even engage us really.
Now, as to your points from before:
1. You don't need permanent flight. If targets have total cover, you Ready your Casting a Spell action for EB for when a target moves from behind total cover and blast it. It's a cantrip, so you don't even have to worry about expending a spell slot if all the targets are pinned down and remain behind total cover for a round.
2. True, none of these features increase your attack roll or damage roll. Except, of course, as you pointed out when you can exploit your increased range to get in additional attacks while your targets are just moving up to their encounter range to attack back. Any of these features for boosting range alone IMO is sufficient for being able to exploit that condition often enough to make selecting one of them worth it. Personally, I chose Spell Sniper for my PC because of the other benefits, it requires no spell points, and the eldritch invocation choice for Agonizing Blast makes it more effective
because it does bump the damage.