Don't confuse "inexpensive" to "cheap". They are not the same. You can get a pretty fine budget receiver nowadays, and have been able to do for quite some time..
As for power, as long as the amps are kept within their operational limits, differences between good receivers (and yours is a good one) are minimal. And, if you think you need more power, keep in mind that to make a barely audible differences on peak draw situations you need at least twice your current power.
Also, when you look at a manufacturer's lineup, you'll notice that as the price goes up the features increase while the power pretty much stays the same form several increments.
IF you think that newer is better, well, there are more features available nowadays like HDMI switching and sound, but that's not what you posted about, is it? You asked about amplifiers. Here's a hint: amplifier technology hasn't really changed that much in many years. There's been some advances bu the question would be "are they audible"? Well, my $$ is on not really unless you break te bank ad go for a much higher priced, much ore powerful unit.
Now, if you want a excuse for a new receiver, HDMI is all you need to say. As for sound, I'm still using a 10 year-old Denon and feed my blu-ray directly to my TV and run the sound to my analog inputs on the receiver so, sound and video wise, I'm right up there with the new stuff.