Google has express concern for how large our model number account is and suggests trimming it down. trimming down the number is not an option.
Are these model numbers getting traffic? I assume no, based on Google's suggestion... one option would be to purge the zero impression keywords periodically.
As it is with 50k kw's its very slow and hard to navigate through.
I'm a bit surprised by this... I've have experience with substantially larger accounts with solid account performance. Perhaps, the sluggishness is tied to your campaign/ad group structure?
I am thinking of getting an My Client Center account to manage our 2 accounts from one login... what other options do i have to manage 100k+ model number keywords?
Beyond the MCC (which is great) there aren't that many options beyond better organizing your current account. I think the MCC is your best bet.