You would expect that you will have a channel drain for your modern look shower, but your tiler just told you that it is impossible as your plumber didn't install the drain in the right position.
For channel waste, it is best to install it abutting side walls, it is not ideal to place them in the middle, but by default plumber will put the drain pipe in the middle of shower base. A good plumber will consult you before they install it, however do not expect you will get a good plumber, so you have to communicate pro-actively, you need to tell them what kind of shower you will have and confirm with them. Sometimes even you the lead plumber, it is still not happening as the information is not passed over to the bloke who actually install them, so double check the work on the spot definitely worth the time.