Bicester Village, a site worth of visiting

My friend from Wales came to see me and stayed in Oxford with us for a couple of days.

We went to Bicester Village again for some shopping and as a tourism site to entertain my guest.

Years ago, another friend told me that he had been in Blenheim Palace for many many times, maybe 7, if I didn't remmber wrong, for showing his friends, relatives around as a fomous tourism site. I was surprised! But, now, I have been to these places many times myself, showing visitors around.

Where Can I show them to visit? Colleges of Oxford university, Blenheim Palace and Stratford-upon-Avon and town center of Oxford, where else?