Using both ARD 3.1 admin and ARD 2.2 admin - troublesome issue

Question

I have searched and found various posts on this, but no comprehensive thread. Many who have used ARD 3 have encountered the "This Task Will Fail - Old Remote Desktop Client Software" when trying to perform tasks on clients with old (pre-3.0) software. It seems a simple task to upgrade to the latest client software, and it is quite easy.
But doesn't anybody else find it odd that if you use ARD Admin 2.2, you can perform all those tasks on computers with the 2.x client software, including copying files, etc. What logical sense does it make that the latest version 3.x admin cannot perform those tasks on a 2.2 client that its predecessor could? You can't even send a simple Unix task such as to repair permissions.
If you put those two together, you may just come to the conclusion that it doesn't matter, because you can just upgrade the client software with a click, and I thought the same thing, at first. But there is a situation I find myself in that is extremely annoying.
I have used ARD 2.2 in my own consulting business for several years with small clients, home offices, etc. But now I was issued a MBP with ARD 3.1 at my day job, so I was able to get rid of my Powerbook G4 I used in my consulting and transfer the ARD 2.2 to my iMac G5 at home. I keep all my personal files on that iMac, because with my router conifigured properly, I can access it from the MacBook Pro from almost anywhere. The iMac retrieves and stores all my personal e-mail, photos, etc.
Without even thinking, I updated the iMac to version 3 client as soon as I got the first "task will fail" error. I then, however, found out that ARD 2.2 Admin will not launch if the same computer has ARD 3 client software-- completely unusable. I had to uninstall the 3.1 client files from the iMac and reinstall 2.2 admin, which puts the 2.2 client on it. So now when I am home at night or connecting from elsewhere, I am limited to only controlling/viewing the iMac. Well, I paid good money for 2.2 admin shortly before version 3.0 came out, and I could not get any upgrade pricing. I don't need anything more than the features 2.2 offers for my side work, so another $299 would be wasted money for the 10-user version. I just think it's unbelievable that the 3.x client disables 2.x admin, and 3.x admin cannot do anything other than control the screen of 2.x clients, not even send a message or lock screen-- again, these are things that 2.2 admin can do with no trouble at all. A 3.x version unable to do things a 2.x version was able to easily do? Does that make sense other than to force an upgrade?
I like 3.1, I use some of the advanced features that 2.2 doesn't have, but this has become quite annoying. More annoying, in fact, than all the failed attempts to upgrade the client software of some of the older Macs at work - no error message, no warning it would fail because the Macs were using 10.3.8 or lower-- just a never-ending task running. I finally figured out that they were not running 10.3.9 and that was the trouble. 3.1 admin couldn't tell me that? Yes, that was pretty annoying.
OK, this has ended up kind of a rant, and I apologize. But if anyone knows a workaround to the above mentioned annoyance managing a Mac with 2.2 Admin on it, please let me know.
Thanks--

Answer 1

Thanks for the info--I did not realize that so much had changed.
It seems to me, then, that at a minimum, Apple could make a version 3.x client which would not interfere with an ARD 2.x admin running on the same machine. It's not reasonable to assume that their customers would need to or have the budget to upgrade all their ARD admins when Apple offers no upgrade options at all. A 2.x Admin machine will often still need to be managed on a network for updates, etc.
If I had paid upgrade pricing for 3.x, I would not feel so strongly about this, I would then feel that I got a deal so that the 2.x client should be retired. But having to buy the 3.x at full price instead makes me feel the need to use the 2.x as long as I can - 3.x is then not an upgrade, it's a separate product. I understand that the Admin app changed a lot, but it would not seem to me such a big deal to make a "universal" ARDclient which could respond properly to whichever version of the Admin was directing it. Apple has a long history of having to do such creative software development.
OK, I'm out. I mark it question answered, but I am going to keep harping on Apple to release a universal client.