I don't think it has ever been "easy" to secure redemption seats. Less so on popular routes or during UK holiday periods. However, I personally always manage two or three First redemptions for two people each year. This year, we have secured returns in First to LAX, IAD and JNB. Being flexible with dates is key and if you want to go to the Maldives in high season travelling First on a particular date, you will probably be disappointed. Short haul, I have always been able to travel Club Europe on my chosen date and time. Even a couple of months out.
As for spending Avios, there are plenty of partner options. Wine flyer and Nectar being two obvious ones that are popular on this board.