Personally, and I’ve got a pair, not a fan of the Aksium’s. Mavic make great rims, but rubbish hubs IMO. I’d go for something else.
Several places are doing Shimano RS10’s for around £100 a pair right now. Not an upgrade, but they’re a good solid wheel with reliable hubs that’s on a par with the Aksium’s. Or you could go for some RS20’s that are a tiny bit lighter.
The Fulcrum Racing 5’s are probably a minor upgrade. Not bad wheels, and a good price from Ribble to be fair.
If you want ultimate reliability though, some 32 hole Mavic Open Pro’s built onto hubs of your choice with DT Comp spokes by an experienced wheelbuilder still can’t really be beaten. 5 years out of a pair of Aksium’s ain’t at all bad though to be fair!