So it seems to me that this could be decomposed into two questions "What was the opinion of German military leaders regarding an invasion of the USSR?" and "what was the opinion of German military leaders in regards to the planned invasion of the USSR?" Somewhat subtle but I'm unsure whether you're asking whether they wanted it or what they thought about fighting it

In regards to the first I can tell you it was a big matter of Nazi ideology (Lebensraum and all that) and that the showings of Ludwig Beck in regards to Czechslovakia seemed to show the German army didn't want a war, you want more clarification I'm sure somebody else could help on an ideological breakdown of the German military

In regards to the second the Luftwaffe were happy because it's the sort of conflict they were designed to have fought[1], as to the rest of the German army? One must understand that this was a generation of commanders who 20 years ago had fought France and the UK for 4 years before losing and then all of a sudden they'd just rolled over France in 6 weeks, yes someone might say a conflict with the USSR was impossible but then they'd said that about France hadn't they? So essentially the German army was pretty happy because they thought it would be easy and they would win[2], that's not to say all them were that way but it would seem the vast majority were

So is this to say it was all hugs and kisses in regards to a hypothetical invasion? Maybe not, apparently some of the logisticians didn't like it one bit and calculated the USSR as a drain but I can't cite anything detailed on that, check out Wages of Destruction by Adam Tooze and I'm pretty sure you'll find more on that front

[1]Bellamy, C 2008 Absolute War "Who planned to attack whom, and how?" [2]Guderian, H 2009 Panzer Leader "The campaign in Russia, 1941"