In a couple of days MHW will launch. I think it's a good idea to look at the performance of MH4U to get a sense of the sales context of the 3DS MH releases in the West:
In general,
MH4U is the only MH game to breach the 1 million mark in the West, totalling
4 million units sold (shipped, but that was 2 years ago) with Japan + West combined. It launched February 13th 2015 in Europe and NA.
- Germany: The game failed to hit the 100k milestone within its first 12 months on the market.
- UK: The debuted at
no. 4 in the combined format ranking. The game's sales should be somewhere between 16,733 and 23,763 units (
thanks BrunoMB!), representing a 95% boost compared to MH3U.
The second week saw a drop to no. 12, with a 68% drop.
The third week saw a drop to no. 20.
- France:
MH4U debuted at no. 2 in France, behind TLOZ Majora's Mask 3DS and ahead of Evolve PS4.
The following week saw it hold on to the no. 2 spot, behind The Order 1886.
The third week saw it drop out of the top 5 as DB Xenoverse and Dying Light launched.
- Spain: In Spain,
MH4U was the second best selling game of February, behind TLOZ Majora's Mask 3DS and ahead of The Order 1886. In March,
it dropped out of the top 10.
- US: In February,
the game sold over 290k units physical and digital per Nintendo PR, and
landed at no. 10 in the monthly ranking for February. In March,
it dropped out of the top 10.
That all I can find on MH4U, hopefully it paints a bit of a picture of MH4U's performance in the West.
Edit: One more thing: The
following leak from NPD insider Creamsugar puts MH4U at 278k after March, which is for the unbundled physical-only sales.