^It helps to have a understanding of the cards and how games play out with the cards before trying to construct an argument against them. Theroymon is cool, but it's useless.
Does it really matter that Vileplume can't be catchered? Coming up with a totally random statement like that does nothing to help your argument or invalidate his. Catcher+OHKO is not a problem because at most you're going to lose a Chincou and an energy and in general Lanturn either comes out onto a field of bigger threats, or in the first 3-4 turns of the game as a direct counter to their first Typhlosion. If you're losing your Chincou to Catcher, that's not an issue with the card but an issue with your timing and playing skill.
You never did say Samurott was better. But no, it's not. It's a stage 2 so it has to go into a stage 2 deck.
DCE is in almost every competitive deck. Since we're talking about beating Reshiphlosion, we can remove Reshiphlosion. We can remove Gothitelle because it already has basically an auto-win against it. That leaves us with googlebox, Stage 1's, Zekrom and DD, Magneboar and Yanmega/Magnezone. All of these decks run DCE except Yanmega/Magnezone and some Magneboar, which already runs through Reshiram. Mewbox already has a great matchup against TyRam and because you can't use Catcher, Lanturn is useless there in the first place. It helps to focus your argument onto decks that can actually make use of this tech (Stage 1's, googlebox, DD) and not just onto random examples that aren't relevant to the point you're trying to make because the tech either doesn't work or isn't needed.
If Lanturn can OHKO Typhlosion, I think that was a great use of the DCE. Zoroark will be OHKO'd too, but you seem to be a fan of putting DCE's on Zoroarks. There is absolutely no pressure to attach to a Zoroark. Popping a DCE on Lanturn should take priority over Zoroark any day because killing a Typhlosion > killing a Reshiram.
If the damage from Rainbow Energy is actually losing you games, that's an issue with playing skill and not with the card. Zoroark and Yanmega are already incredibly frail and the 10 damage makes no difference. Donphan is the only thing it matters for, but after actually testing it you'll realize the one place it mattered significantly was against Reshiram, but that's the whole point of Lanturn in the first place.
Lanturn is easily splashable in any of the three decks that can make use of it. If you think a 2-2 line is needed, you missed the point of the card. A 1-1 line does the job fine. Dropping Basic Energy for Rainbow Energy does nothing to take up space when there's no basic energy search in the format.
I would not want to go into a tournament with the Stage 1 deck and not have a 1-1 Lanturn in it. Mostly because of Gothitelle and Vileplume, but it's great against Reshiram too.