That's one of the disadvantages of the Avios program, but it was true about BA before they made the change. BA's FF program had lost some of its value when fuel surcharges became a significant factor. You'll pay $600 or more in surcharges to Europe and that figure will crack a thousand for flights deep into Africa and Asia.

BA works much better as an upgrade program to business or first-class travel. Taking advantage of a sale in November, I bought a World Traveller Plus ticket IAD to LHR for a little under $1000. Then with 22,500 BA miles/Avios (the program changed after I did an upgrade for the trip to LHR, lowering the redemption cost from 12.5K to 10K when I was able to book an upgrade for the flight home), I upgraded this flight to their business class product. Since I paid for a ticket in WT+, I earned miles for flying at an enhanced rate as well, meaning I spent about $1100 and 10K of my miles to get a seat that would have probably cost around $2000.

For me, that's a worthwhile discount for a product I want. Others may not place that high a value on it. One more situation where Avios may have value for economy flights to Europe: where you end up needing a flight on short notice. $600 or so in surcharges isn't cheap but might save you money if you need to fly to Europe on a couple of weeks notice since the fuel surcharges do not go up for that redemption.