If the reward for solving a block is truly unknown until after it is solved, then it is improper to assume any block reward value based upon past results. This is basic statistics and simple game theory otherwise known as expected value. For dogecoin, the proper assumed value should likely be statically set to 500,000 when deciding which coin to mine. As I type this message, the expected reward value is currently set to 736,000
Hopefully poolwaffle chimes in here, but he has addressed this a few times now. According to him, the block reward isn't random when it is being mined. It isn't being assumed. The very moment we are mining it, it is known what the block reward will be so those stats are exactly accurate. Here's a quote from poolwaffle on the wafflepool subreddit:
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But the reward is known ahead of time. The first transaction of every block (coinbase transaction) is a transaction with blank inputs, to the output you decide (typically the pool, or miner). That amount needs to be known ahead of time (or have a way to be confirmed as correct), or else everyone would be mining blocks with randomized coinbase amounts. Since it is known to the people mining for the block, we check what it is, and use that as the reward 
As for individual worker stats, he's addressed that a couple of times and it is in the plans but profitability tweaking and some other features are higher on the agenda (rightly IMO) and as for historical hashrate charting, we can already use wafflestats at http://waffles.wilschrader.com to do this for us thanks to the added API.