I wasn't meaning the level for the wealth tax kicks in at £100k.
I'd have it around the £5m and upwards mark, personally.
But someone may own multiple assets of a few hundred grand each, so you need a mechanism of being able to total up everything of at least a certain value.
On paper think this is a good idea - thinking of chattel rules with HMRC, an asset/group of assets need to exceed £6k to be of interest to them (heavily simplified here for ease of example) and maybe use this as the point at which something counts towards the wealth calculations.
You aren't going round the house totting up laptops and tvs for example but rather "major" items such as cars, expensive watches etc which you'd likely already be insuring and you would want to keep a good idea of their value anyway.
In terms of filing the declaration - Nobby is right that most people don't even need the services of an accountant to do the normal SA return but even for those who do use one your basic tax return is only £200-£500 plus VAT. When I say just I know to many these are big amounts but if you have yourself £100k in assets or more then you can likely spare that much if you need help with it.
I like also the idea of excluding your primary residence as it aligns with current tax rules around tax relief for CGT on sale of primary residence so would be built on the laws already in place rather than a complete re-write