The scrutiny is as intense and they actually expect you to have more proof because now you have 21 months more of marriage where you should have your joint accounts, joint estate planning, utility bills, insurances, pictures, etc. all worked out and generating a paper trail. I know a few and have read many more folks on here and other forums whose I-751 package goes easily 400-600 pages of evidence. Jaycel and I have about 200 pages of stuff saved up already. The instructions for Form I-751 specifically say:
Evidence of the Relationship
Submit copies of documents indicating that the marriage upon which you were granted conditional status was entered in “good faith” and was not for the purpose of circumventing immigration laws. Submit copies of as many documents as you can to establish this fact, to demonstrate the circumstances of the relationship from the date of the marriage to the present date....