Ha! Well, actually our 401(K) is great because my employer pays ALL the management fees on the mutual funds—I moved my old IRAs in as well.
Are you saying that your employer is paying your costs of your IRA funds that are now in your 401(k), as well as your 401(k) contributions? Even the federal government's Thrift Savings Plan has an expense ratio, although it's tiny. Have you been able to verify that you're not being charged through some complicated/confusing compensation reimbursement?
Regardless of who's paying, how much does your 401(k) provider charge? Would you rather that the money going to the provider be deposited to your account balance instead? Just the mere presence of a "free" advisor makes me suspect that someone is paying that 401(k) provider an above-market rate-- or using the discussion as a sales meeting.
Whether your employer is paying the 401(k) provider or you're paying the 401(k) provider, the advisor's fiduciary duty is to someone other than you. In my opinion, that renders their "advice" to be suspect... even if was advice that you'd normally agree with.
And if that advisor still thinks that age 70 is a realistic retirement age for everyone then I wonder how her family & relatives react to her advice.