With the bonus being in for a few days, I don’t think it’s significant enough to matter. It’s there, sure. But I don’t find myself any more willing to play incomplete, unspaded lineups to grind new parts of a tree, working towards strong vehicles or lineups, etc. I’ve continued to just play what I already have, because the grind past Rank IV right now is still unbearable, especially as compression continues to be unaddressed.
I think that makes a few changes more obvious, maybe? Part of the general disinterest in new nations’ additions is due to the ever-increasing RP grind, but I think a large part of it is also that the gameplay is very very inconsistent across the BRs, across ranks, across lineups, and even when you look at individual vehicles if stock or spaded. The RP grind is long and tedious, but it’s unbearable chiefly because of BR compression, a poor stock experience, and so on.
To be clear: this change is good - I don’t think it’s enough, even if you pretended the RP numbers were the only relevant thing - but, at minimum, keep this feature, with its current potency, but seriously consider increasing the bonuses.
In addition, a lot of work needs to be done for the grinding of modifications and the performance of completely stock vehicles. The combination of a buggy repair system for vehicles without parts, some vehicles lacking any real killing power until further into their mod ranks, and some vehicles simply having even worse performance in areas that their spaded version is average or sub-par in - these all contribute to making it difficult to justify spending time playing a new vehicle or lineup of vehicles (probably unlocked using this feature) when there’s sure to be a full lineup of spaded vehicles in another nation the player can easily play and enjoy without much effort.
Some vehicles (or really, entire BRs) aren’t at all enjoyable even after spading them… unless you get a downtier. This is textbook compression. This only goes double for stock vehicles, but some spaded vehicles also just simply can’t perform well in uptiers. Some can’t perform well in their own BR! The research bonus is only available for three matches - so what if they’re all uptiers with vehicles that can’t match what they’re facing? The transition to better types of tank rounds, 2-axis stabilizers, thermals… afterburners, supersonics, advanced missiles, advanced radars… the proximity of vehicles with these features to vehicles without them means that sometimes, even if you grit your teeth and spade your chosen vehicle/lineup, your three games with boosted RP might just be ended by a full uptier.
There are also crew skills that an experienced player, with a top vehicle in another nation, may be very used to. A fresh crew suddenly means that your tank doesn’t shift gear on time, your turret magically traverses slower, your repair times are much, much longer… Cultivating a crew takes much longer than grinding even an entire tree does, and this feature doesn’t improve that either.
To sum, this feature only addresses the numerical problems of grinding a new tree, and not enough. Stock vehicles are too inadequate, which, to be fair, is a separate issue, but regardless of what a vehicle can and can’t do stock, this feature should affect the RP rewards that go towards modifications, at a bare minimum. It should also affect crew skills - even if the above are addressed, when someone finally purchases the final vehicles of the tree and say goodbye to their bonus, they’re still left with performance noticeably worse than people playing their main nation with Lvl 150 Expert crews - a key part of the “Top Tier” experience that this feature also fails to help provide.
And as accessories to those changes, it would be a godsend to make an effort to decompress, obviously in ground, but also in air. The not-so-recent round of decompression for top tier jets was nice, but I don’t think anyone wouldn’t say that it was also very very messy - which is a result of putting decompression off for so long, and then suddenly moving the top BR up two steps and trying to redefine the balance of what had been 9 BRs of heavily-compressed vehicles into 11 BRs that are now inconsistent and still quite compressed. Future decompression should be consistent, and fairly conservative: move the top BR vehicles up one step every round of BR changes, at least for a year. And for BR changes in general, if a vehicle is overperforming, move it up. If that vehicle is at the top BR level, then move it up anyway.
Finally, look at stock syndrome very closely. Maybe - and I’m not sure how’d this work - figure out a way to see the average Efficiency for a vehicle with the unlocked modifications for the database figured in - maybe separated, maybe weighted, I can’t say. Either way, there needs to be a system in place that makes vehicles with painful performance gaps between stock and spaded easily identifiable. Also, repairing without parts is a horribly buggy mess that can simply ruin the first games using a vehicle.
The problem this feature is trying to fix is that players are unwilling to spend an exorbitant amount of time grinding a new tree. I don’t think the reason for that is entirely for the long grind - though it needs to be shortened either way - but instead that long grind means that they need to spend that long suffering through compression, odd balance, and a poor stock experience. Shortening the grind means the time spent suffering is shorter, but it doesn’t address the suffering itself, and anyone with what I think is a good deal of self-respect is going to refuse to engage with that experience unless it becomes as short in the future as it is long now - with WT’s monetization, I doubt it’s a good idea to make this feature’s bonuses that powerful.