The whole tribunals system continues to be a bit of a mess. It's not terribly accessible and the attempts to restructure the non-devolved ones has been (with scarce few qualifications) a complete disaster. The devolved ones are even worse and they're becoming the complete antithesis of what they were set-up to be. The whole point of the tribunals was to provide more proportionate and more accessible dispute resolution that wasn't like the courts.
I don't buy into the idea that this is an overtly political anti-worker change but it does sound like they're doing nothing to improve the situation. You can bash on about it being anti-worker all you like, but you should also bear in mind that for small-medium sized businesses the Employment Tribunal process is very expensive and often a completely disproportionate way of dealing with the substantive dispute. I would be more concerned about the cuts in legal aid and the sporadic availability in the tribunals compared with the courts.
On the statutory instrument point, this isn't the Coalition's fault either. It's completely normal for the detail of administrative operations (for example, the Prison Rules) to be contained in and amended by Statutory Instruments. Whether that should be the case is a legitimate point of dispute, but it's not something that's new and it's not something that Labour are exactly opposing. There is actually a huge advantage of it being delegated legislation as it means any breach under the European Convention on Human Rights would render offending provisions bad law and void. If it were covered by primary statute it would be unchallengeable in the courts.