I feel that you are too kind for Lindell here.
And you are seriously undervaluing Lindell. He has been very good this season, and he showed already last season some glimpses of it. He is nowadays also a quite good physical presence whom can skate pretty well for his size and has pretty ok hands even. Quite a perfect match with Klingberg.
What would Heiskanen and Klingberg really do against big and fast opponents that can cycle the puck well? I can tell you, they would be in trouble in their own end. Balance and the right roles is what is needed for creating good lines and the same applies to defensive pairings too.
Either Klingberg or Heiskanen with Lindell and the other one with Methot, could really work nicely, at least if Methot can still recover himself to the same level that he was at best in Ottawa. He was a very well working pair for Karlsson there. A big, strong and reliable stay at home defenceman, who’s play allowed Karlsson to do his excellent offensive hockey without being too often scored against. Now that Karlsson is not playing anymore with Methot he is in trouble with his ultra offensive style. And now Ottawa does not have anyone else that is in the same class of Methot as a clear stay at home defenceman.
Miro can sure defend, but I can still see him having quite some problems with the big and fast forwards whom can protect the puck very well. He will most probably need a Lindell or a Methot to help him with those kind of players. And also having a stay at home defenceman with him, will help him use more of his excellent offensive skills. And the same applies with Klingberg.
Sure, put Klingberg and Heiskanen on the power play at the same time on the blueline, it could be really something. But on 5 on 5 they would be together a too big risk in their own end, especially because of the lack of strength and reach.