The way Kishi handled the war is what ruined the manga more-so than the Edo Tensei Jutsu. Edo Tensei actually allowed Madara to realize his full plan. Without it, he would not have achieved what he was looking for. Not only did both Nagato and Obito betray him, but he would have fought a war as an old man if he was revived the way he planned.
Bottom line? Without Edo Tensei Madara doesn't become the Juubi Jin. Not only that, but Edo Tensei allowed us to see a great variety of shinobi that would not have been shown otherwise. Was it all good? Not at all. The war was comparable to the Arrancar arc in Bleach, which completely ruined that anime. If Kishi found a way to break up the war or reduce its overall duration without loosing the meaning, it would have been better.
But without a doubt, Kishi would not have been able to realize his full vision without Edo Tensei. That is why he utilized it so much so.