I am the APA masta! Seriously, though, it's my favorite style and about 1/2 the brews I make are APAs.
Centennial is a GREATTTTTT flavoring hop for APAs. Very smooth.....one of my favorites as the 15 min addition.
BTW, if the beer is 70 IBUs, it is no longer an APA, it's an IPA. APAs top out at 45 IBUs. 7% ABV is also out of range for an APA, and would be in IPA range. I also don't exactly get wanting to use German Malts (munich/vienna) in an American Pale Ale either. Not an APA anymore if you make it with German base malts. Actually none of what you are describing is consistent with an APA. But anyway
Try this. I've made a similar recipe with two row, and it was great. Should be great with Maris Otter to give it the extra malt kick you are looking for. I also bumped up the Maris Otter a bit off my original recipe and bumped the hops a bit to maintain the balance. This should be a good APAishhhhhh beer:
5.25 gallon batch
12.0 lbs Maris Otter
0.75 lbs Crystal 60
0.5 lbs Honey Malt
1.25 oz Cascade @ 60
1.25 oz Centennial @ 15
1.25 oz Centennial @ 5
Safale S-05 yeast
Mash @ 156F for 60 min
Ferment @ 59F for two weeks
Bottle/Keg condition carb for 2-4 weeks at room temp
IBUs 45
SRM 11.1
OG 1.071
FG 1.02
ABV 6.75