So you'd rather the case be decided by a single lawyer^H^H^H^H^H^H judge than a panel of lawyers. Even in common law jurisdictions, most of these sorts of cases tend to focus on disputes over issues of law (hence tried by a judge), not issues of fact (which are the only issues which proceed to a jury trial). Judges are usually lawyers before becoming judges--that's not terribly surprising, considering that judges are expected to know a lot of legal theory, which is essentially the same training you undergo to become a lawyer.

Fearing the provisions of ISDS would undermine the principles of justice means that you would rather trust the judgements of a single, likely overworked, lawyer who is expected to know the entire relevant body of law and case history for his or her jurisdiction over the judgements of a panel of lawyers who are likely to have somewhat specialized in the area of dispute being covered.