Toni, Thanks for a very interesting article! I do agree with their point numbers 1 & 2; riding the bus is a lot more fun in London than riding the tube. You see a lot more. Also, if you see an interesting shop or cafe out the window of the bus, you can hop off at the next stop and walk back to it. The tube is fast and convenient, however.
9/10--Skip the visit to Piccadilly Circus...I totally agree with that. To first-time visitors to London, I would say, you'll get a glance at Piccadilly Circus from the hop-on-hop-off bus (or a regular city bus) and that's enough.
3/4--Skip afternoon tea...I agree with that. Especially skip it if it's ridiculously expensive. It's just tea and cakes, and you can get that at a neighborhood bakery mid-afternoon, for one-tenth the price. Try The Hummingbird Bakery in Camden. Cup of tea or coffee, one fabulous big cupcake, under ten dollars.
7/8--"Don't think you can see everything in three days...Prioritize the things you most want to see." Good advice for the first-time visitor. I would also add, read your Rick Steves London guide or English/London history before your trip, so you can decide what sights really interest you. Some first-time visitors to London seem to know nothing about what's there, or the history of the city. That's a shame; because they may miss out on something they'd really be interested in, if they only did their homework before going. (And yes, that includes coming here and asking us our advice on what to see.)