I'd love to see more "old fashioned" food on menus. Such things as faggots (proper ones) and peas, liver & onions, steak and kidney pudding. I'd also like to see more old fashioned veg served with pub roasts, like mashed swede, leeks or runner beans rather than the ubiquitous carrots, broccoli or French beans.
When it comes to desserts I rarely order one when out these days. It doesn't matter where you go, the choice is always some concoction involving chocolate brownies, sticky toffee pudding or cheesecake. I like the latter, but not all the time. What a treat it would be to see a steamed fruit pudding, apple charlotte or an oven cooked rice pudding for example. I guess most places just buy catering packs of desserts these days and people have a taste for more "Americanised" puddings.