Would it be advisable to grind loose green tea to fine powder to increase the flavour concentration ?
Also, please share your opinions on the pros and cons of this method.
Grinding tea leaves will help to extract more flavour from the tea leaves faster. The logic is simple. After grinding, there's more 'tea surface' that can come in contact with water. Real life proof in practice is that when you compare grinded tea in a teabag compared to full leaf teas. Tea bags release most of the flavour in the first steeped, while full leaf teas taste lighter and can last for 4-5 steeps easily.
However, grinding leaf tea wouldn't make much sense, since you can get tea bags; or if you need something super fine than you can get matcha powder. Very difficult though to grind your own matcha. For a real matcha, the stems and nerves of the leaves are carefully removed before grinding and turning into powder. It's something really hard to do by yourself. Let alone the machines you need.
Grinding should not increase the flavour concentration, unless you mean increase the amount of tea you can fill a container. The quantity of leaf and steep time would play a bigger factor in the strength of flavour. However, if you powder the tea the main benefit would be shortening the steep time. Which can also be a drawback as you have a higher chance to over steep and bring out unwanted bitter and/or astringent properties out into your tea. For more information on powdered green teas and usage, look up "Sencha" and "Matcha".
Note: If you are wanting a stronger tea flavour you should consider the stronger end of the tea spectrum. Such as Oolong (e.g. Tieguanyin aka Iron Buddha) (e.g. Pu-erh, Goishicha) or Post Fermented Teas.