I can barely fill up my ISA, and I use the CGT allowance to utilise multiple accounts outside of the annual deposit limit. The reduction of CGT allowance would further restrict my ability this.
To be fair, we can invest 20k of new funds a year tax free, and then get an additional 12.3k of CGT and 2k of income allowance a year. Not many can utilise all 3 let alone the 20k, why not simplify it, and just have the 20k ISA allowance?
Have everything outside an ISA taxable at source and at the same rate, allowing historical losses to carry forward. For multiple accounts it would require a linked up tax system, but simplifying the tax rules would make that so much easier.