After discussing this with the Systems Team the issues seems to be caused by a number of factors. No direct change to the repair costs were made. However, due to how repair costs are incurred the combination of stronger mobs, combat changes, new stats and the increased speed of combat, have come together to result in increased item wear which in turn results in increased repair costs.
The team is currently looking into how best to address this. There is no 'easy' way as the issue is caused by a number of variables and there is no 'switch' to throw.
As with all new systems and major systemic changes we'll continue to look at the data and make adjustments accordingly.