I didn't know it was so out of date. I just happened to see that recent article as a link on N4G. Kind of dirty EA doesn't support Wii, but at the same time I do understand why.
"difficult to convince gamers to jump into sequels" You are absolutely right. Even I am like that. I jumped on ME2 because I had played ME1 at my cousin's house, but pretty much EVERYONE gets on their knees for Witcher 3. I think they have it so hyped at this point for people that have never played it that it can't reach the expectation off of the buzz people have created for it, but I just have no desire to play it. If they had an edition with Witcher 1 and 2 included? I might be interested then, but for me to just go buy and start on Witcher 3? I couldn't care less. I may get it one day in future as an Ultimate Edtion for 20 bucks or something, but I have no interest starting a series on its third installment.
The Witcher 3: Wild Hunt is a great game. That being said, I'm a PC gamer, and I've played TW1 (only on PC) as well as TW2 (PC only until it came to X360 a year later). While you will certainly enjoy TW3 without playing the first two, it's not going to make very much sense. You also won't know any of the characters, and there are a lot. It's the equivalent of jumping into ME3 without playing ME1 and ME2. It would be great if TW1 and TW2 could come to current gen consoles, but I don't see it happening. If I were you, I'd pick them up on PC. Especially on GOG (owned by CDPR, who makes TW games), TW1 and TW2 are usually $5 each half the year.
For day one sales? I think since its only going to be a next-gen game(not WII U imo) I think day one sales will be close to 1-1.2 million copies sold which is like 60-72mil. Overall I think the total sales will be close to 4-5 mil, which looking at VG Charts for Dragon Age: Inquistion (which can be totally out of date, so forgive me) has sold just over 4mil worldwide. 4 -5 million copies would equal to around 240mil to 300 mil.
Mass Effect 3 generated 200mil after 2 months sold, which is pretty decent so I think the 240-300 mil prediction is a good guess.
Now I can be totally wrong and maybe it will sell 10mil copies(I hope) but we'll never know until its shipped.
MEA will be a failure if it's only selling one million copies in its first day. Fallout 4 sold about 12 million by the end of its first week, if I remember. Assuming marketing is great and anticipation is high, the game should be able to easily shatter any record of previous Mass Effect games. Dragon Age Inquisition might be hard to beat just because it was available on five platforms, where MEA will only be on three platforms.
If the game is good, receives good reviews, and generally has a positive perception, it should sell like hotcakes. It's easily one of the most anticipated titles of the year. Most of the heavy hitters came out in 2015, so MEA has plenty of space to just dominate.