I totally agree that it will be expensive. However, as we already know inflation has a way of making things more expensive over the years. You have to agree with me though on the fact that there will be a satellite at 73 at some point in time regardless of whether it is Nimiq 4 or Nimiq 5. Bell would not have to move existing channels to Nimiq 4 at 73 right away. It could be used to supply additional HD channels. For example there are a whole bunch of channels such as TLC HD, History HD, Space HD, Spike HD, (to name a few) that as far as I know Bell has not added yet. By initially only using Nimiq 4 to add new channels, they would not be forcing many people (i.e. people happy with their existing HD line-up - whether they have an 8PSK/MPEG-4 capable box or not) to make the hardware upgrade and thus have to send a tech out to upgrade that many dishes.
Also, I do aggree that when Nimiq 4iR runs out of fuel that will be a problem but like scrooloose said "Nimiq 2 has plenty of life" and the channels on the few transponders that are down on Nimiq 2 can at that point in time be moved to Nimiq 4 at 73. Just look what Bell did with the HPI-1,2 channels. Were on Nimiq 1, now on Nimiq 2. If you still want them then you will have to upgrade. I would still suggest they go ahead with the transition to a 3 orbital location now before the recruit too many new customers as HDTV prices are only falling lower and lower as the years go by. Like you said granduncle "...every customer using this satellite would need a tech visit" but only if they didn't have a setup that included 73.