I'm not a native English speaker, so correct me if I'm wrong, but I think English needs a new word related to pepper spiciness, for me sometimes is difficult to translate it. In Spanish we have "picoso" to describe pepper's hot feeling.
Since spicy in English could describe a long variety of spices, flavors and sensations. Maybe 50 years ago it wasn't necessary since they were foreign flavors, but now that your food and taste has evolved and globalized it could be necessary.
Yes, very much so. Eating a curry and saying it's "hot" can equally mean it's very spicy ( phall etc ) or it is physically too hot to eat yet. We tend to say "it's hot-hot" for physically too hot or something like "it'll blow your face off" or "this curry is really hot".
It's a minefield of ambiguity which a new word could easily solve. It could well be, as you say, it's only recently that hot spices have become mainstream.
I grew up in the 1960s & 70s in northern England and as a kid my parents may put some very old pre-ground pepper on the table occasionally. Garlic didn't exist to us. I burst out and enjoy hot, bitter, gnarly flavours.
For "spiced" we also have the word "seasoned." It has a handful of meanings, but if you're using it to describe a flavor it should be clear that's the meaning you're using.
I've also heard foods described as having "bite" to indicate that they have a strong, spicy flavor, but not necessarily a "hot" one.
As a native English speaker, we have the same problem. Piquant is used to describe the heat although most people aren't familiar with it. "Capsaicin feeling" is often referred to as well.