You properly hit on your personal pros and cons. What other people would do is irrelevant. No right or wrong answer, all depends on personal preferences.
I'll simply share my family's preferences, as maybe some of the comments are relevant.
My family happily bought into Riviera. Personally, we aren't going to "economical." If we wanted the most economical decision, we wouldn't buy
DVC at all, we'd rent off-site condos for less money. It's not like SSR is cheaper for the same product -- It's simply not as nice a resort, in my family's opinions. Others may disagree, especially if they love being close to Disney Springs. (We don't care about Disney springs, which we just see as a shopping mall you can find anywhere, but with a couple Disney stores).
I do think AKV is the best WDW resort for a resort-only vacation, where you don't even hop to other resorts. Outstanding restaurants and a Savannah! So you have an attraction right from your room!
That said, AKV just isn't a great location for a full WDW vacation, having to rely on buses. Plus, it's usually pretty easy to book a AKV 1-bedroom unit at the 7 month mark, no matter where you own. In fact, I'd say it's pretty rare that you wouldn't be able to book at the 7 month mark.
Thus, if I wanted to split by trips with 50% at Riviera and 50% at AKV, I'd buy at Riviera -- knowing it's not hard to get AKV at 7 months.
Couple other thoughts on the Riviera -- We actually love the pools for a couple subjective reasons -- First, no matter where your room is, the whole resort is compact, so both pools are just an elevator ride and few steps away. The pools are spacious and relaxing, and rarely get over-crowded. When my kids were younger, we loved an "active" pool like Beach Club Stormalong Bay. But with older teens, we now prefer a more laid back luxurious pool setting.
One more thought on "resort only trips" -- As I said above, AKV is the best if your trip is never leaving your resort. That Savannah is a huge selling point. But, there are huge advantages of "resort only" trips at other resorts as well --- From Riviera, you are a quick skyliner ride away from the Boardwalk area, where you will find dancing, bars, more restaurants and activities. From a monorail resort (BLT, Poly and VGF), you'll find locations where you can watch fireworks outside the park, you'll have lots of great dining options on the monorail.
So if you want to never leave your resort, AKV is great for a resort-only trip. But the other resorts are potentially better for a "resort area vacation."