I'm not aware of any specific deliberations with respect to other denominations of coins. What I can say is that there is historical precedent with respect to removing coins from circulation such as in the case of the penny, which was designed to reduce costs with respect to penny production.
The comments you made earlier with respect to the $8-million increase in domestic coinage costs for 2017-18 is more of a reflection of adjustments to the Royal Canadian Mint Act that put back into place certain provisions that would ensure that the mint itself could generate enough profit to sustain operations.