Actually, that's quite a tricky question, (((( Warmie )))).
I'm tall, and I'd like to think that I'm gentle, kind and caring. But, I'm very much aware that I have my defects and failings too. ( Particularly, those that arise from my depression/anxiety. ) And, anyway, I'm not at all sure that you could extrapolate the whole physical/emotional character of two million or so Welsh people from one example, in this case me.
And, to be realistic and honest with you, I'd have to say that the Welsh are as capable of being tall, gentle, kind and caring, ( Or, short, violent, unkind and callous, for that matter...

), as any other person or group of persons.
And, just to further " muddy the waters " the Welsh are a famously diverse, ( OK, perhaps I mean argumentative...

), people, that may be hard to generalise about anyway.
For example you have, ( In no particular order, and this is SOOOO NOT a full list...

):
The Cardiff/Swansea divide...( Cardiff was officially designated the Capital City of Wales/ Prifddinas Cymru back in the 50's. And I don't think that the People of Swansea were pleased about that. Swansea was, afterall, also a well-established city. Also, there is a SERIOUS rivalry between fans of Cardiff City Football Club and fans of Swansea's football team. )
The Cardiff/Welsh Valleys divide. ( " Soft semi-English city-dwellers" / " Semi-civilised barbarians ", depending on whether the speaker lives in the Valleys or Cardiff...
Some Valleys people have been known to disdainfully refer to Cardiff as " just a suburb of London ", and therefore not " really " Welsh at all.
Then again, there is a joke about a Valleys public library that was in danger of closure when all it's books were stolen...Both of them! )
The West Wales/South Wales/Mid Wales/North Wales divide.
The English speaking/Welsh speaking divide.
Etc...Etc..Etc...
( In fact there's an old joke that if you put ten Welsh people in a room, you'll get eleven different opinions!

)
But, that said, I do think that the Welsh are , by and large, a pretty warm, caring, kind, ( If not necessarily tall. ), people. Perhaps, that's because the Welsh are, like the Scots and Irish, part of the " Celtic Fringe. " And, therefore not as " reserved " as the English are?
Also, the Welsh lived in smaller communities, like the coal-mining communties of the Welsh valleys, or the agricultural towns of rural Wales. So, perhaps that led to a greater sense of " community ". ( Even, today, the population of Cardiff, the Capital City of Wales , is only about 330,000. )
However, just because we Welsh can be gentle, kind and caring, doesn't mean we're " pushovers "!

When Edward I invaded Wales, an extensive network of castles were built across Wales, and given to loyal English " Marcher Lords " that could be counted on to keep the recently-conquered ( ? ) Welsh in check. I remember being told that the density of these castles, ( The number of castles compared to the surface area of Wales that they were intended to control. ) was actually the highest density of castles to area in the world!

The Welsh can be a stroppy lot!
( Indeed, to this very day, the English still believe that THEY conquered US...We can be subtle too...!

)