It should only affect "multi-millionaires" with large uncrystalized gains.  The change is only to gains larger than $250K per year. Would you have difficulty keeping your annual cap gains to less than that? 

Say someone has 300,000 CUU shares at a 20 cent average. If SC gets sold for $1.20 (as an example) that person is alrady over the $250K limit in capital gains and he/she is not even close to being a millionaire, let alone a multi-millionaire. Than person would pay over $13,000 more in taxes with the new rule.

I have 90% of holdings tucked away in TFSAs now.

Smart move; I hope everyone has their TFSA accounts maxed out, then RRSP accounts and only after that use regular trading accounts if money still available :)